Oil Immersion - Cleaning technique

[N3ptune]

Hello I ordered a couple of things already, to use my microscope such as slides and oil immersion Type A. Then I found a procedure on how to use the oil immersion technique with the right objectives. But, it's not 100% clear for me, how to properly clean off the objective.

I watched the following procedure which I like:

#1. Using the lens paper to absorb the oil from the tip of the objective.
#2. Using lens swab + lens cleaner, moving the swab with cleaner gentility in a circlar motion, on the objective.
#3. Once that is done, 1 drop of Ethanol on the lens paper again and gently passing that paper over the lens until everything is absorbed by the paper.

I saw elsewhere that methanol can also be used to clean lenses.. I just want to buy the exact product that will not damage the optics. If I buy Ethanol what kind is it exactly is it the kind you can buy at the pharmacy or it's a specialized product?

Anything else I could use instead of Ethanol?

[Microscopy_is_fun]

The allowed solvents for cleaning depend on your microscope. Ethanol is ok for many objectives (mostly the modern ones), but detrimental for others where adhesives (e.g. for mounting lenses) are used that swell or even dissolve in the presence of ethanol.

Therefore it's best to read the recommendations of the manufacturer of your specific microscope.

[Alexander]

Forget lens paper, swaps and all that fancy stuff. Toilet paper is good enough to clean up the immersion oil. The solvent depends on the make of the microscope, as stated above. Many daily users of oil immersion don't clean at all. They just leave the oil on the objectives.

[N3ptune]

The allowed solvents for cleaning depend on your microscope. Ethanol is ok for many objectives (mostly the modern ones), but detrimental for others where adhesives (e.g. for mounting lenses) are used that swell or even dissolve in the presence of ethanol.

Therefore it's best to read the recommendations of the manufacturer of your specific microscope.

Ok I checked the manual, they talk about a alcohol-moistened cloth there, should have thought of checking the manual first (the RTFM thing lol) fortunately I haven't ordered anything I own 99% Alcohol or 70% already. I guess 99% would be a better choice?

Forget lens paper, swaps and all that fancy stuff. Toilet paper is good enough to clean up the immersion oil. The solvent depends on the make of the microscope, as stated above. Many daily users of oil immersion don't clean at all. They just leave the oil on the objectives.

OK good to know that it's not a big deal after all. I will try with toilet paper and see, I probably can return the paper and the swabs.

But, I was told many years ago that it's not recommended to use wood based tissues on optics, like people cleaning their glasses with toilet paper or Kleenex, not 100% sure if it's true.

Nobody believes me anyway so

(I could google it actually)

[Microscopy_is_fun]

Ok I checked the manual, they talk about a alcohol-moistened cloth there, should have thought of checking the manual first (the RTFM thing lol) fortunately I haven't ordered anything I own 99% Alcohol or 70% already. I guess 99% would be a better choice?

I will try with toilet paper and see, I probably can return the paper and the swabs.

The immersion oil is not compatible with water. I would therefore also prefer the 99% alcohol. If you have already lens paper, i would use that. Toilet paper might contain recycled paper, and then you can have all kinds of abrasives in there.

[josmann]

I use Cargille Type A with my high end immersion lenses. I have 99% methanol and 95% ethanol (IPA denatured) as my solvents.

95% ethanol on a kimwipe with very light finger pressure almost always cleans all the oil from the optic in a single wipe. I've had way more success with ethanol than methanol for whatever reason. I usually clean excess around the lens first so I don't wipe oil from the metal onto the glass. I tried a bunch of fancier approaches at first but now this is my standard as the results are great and it's a lot less effort! As long as you're using a fresh wipe I think the risk of damaging the lens is very low. I've found that having a stereoscope around is really nice for inspecting lenses and cleaning them as well (not to mention, also a great microbehunting tool).

[dtsh]

Ok I checked the manual, they talk about a alcohol-moistened cloth there, should have thought of checking the manual first (the RTFM thing lol) fortunately I haven't ordered anything I own 99% Alcohol or 70% already. I guess 99% would be a better choice?

For cleaning I don't know that it matters, but for disinfecting you want 70% as the water helps.

But, I was told many years ago that it's not recommended to use wood based tissues on optics, like people cleaning their glasses with toilet paper or Kleenex, not 100% sure if it's true.

Nobody believes me anyway so

(I could google it actually)

My understanding on this is that you are correct, wood based fiber shouldn't be used as there can be abrasives.

[charlie g]

Hello, 'N3" ..I use 95% ethanol ( available from liquor stores as: "Ever Clear")...I do use lens tissue only because I trust ( what do I know) that these products specifically rule out abrasive contents.


With my slides...I use regular paper towel cut into small strips for use on slides. I used to use IPA 70%...never had a problem with it, for both objective shut-down, and slide shut down...it's the wetmount slides which contain huge abrasives...so you water flush the slides after use, then do the alcohol/ paper shut down.

I suggest prevention is the key: 1) learn how to use the smallest drop of immersion-oil when you use an oil-objective on a slide. In the bench area with dim light...place the smallest oil-droplet on the slide....then 'pull that drop in to center by gently touching it with your oil-objective...and lifting up the objective to break oil bridge contact....then gently re-contact the slide/oil/objective bridge.

2) learn how, with wet mount slides you make...to have the 'sweet-spot' thin water colum beneath the cover-slip before you dare employ an oil-bridge objective on your wetmount slide.

Always avoid the borders of the cover-glass on you slide when employing an immersion oil objective on your mucky yet fascinating wet mount slide. Prevention of mucking your oil-objective demands you think about larger rectangular cover slips ( to avoid the border areas of the slide, yet have awesome terrain to observe.).

3) Always, always, always DO NOT use an oil-objective on a fixed/Permanent slide...until you understand the thickness of that slide. Y ou need then to see which working distance your oil-objective is compatible with...often permanent slides are 'too thick' for oil-objectives. ( Diatom Lab of Italy sent me cherished purchase/ low cost radiolarian fixed slides...and this microscopist in print told me: 'you must not use oil-objectives with these slides'.


Limit the gunk of immersion-oil around your objective lens-face...by learning the smallest oil drop for your objective.

I too heard of particle abrasives in some cottons, in some papers...so I use 'lens paper' (out of trust!). all the best, charlie g

[dtsh]

3) Always, always, always DO NOT use an oil-objective on a fixed/Permanent slide...until you understand the thickness of that slide. Y ou need then to see which working distance your oil-objective is compatible with...often permanent slides are 'too thick' for oil-objectives. ( Diatom Lab of Italy sent me cherished purchase/ low cost radiolarian fixed slides...and this microscopist in print told me: 'you must not use oil-objectives with these slides'.

Any idea why? Due to the worry of crushing the slide? That fear at least I can largely ignore. I use mine with oil many times when I use it.

[BramHuntingNematodes]

I would assume so as the technique with non-spring loaded high dry objectives is to completely lower the lens into the slide while observing from the side, then focus up. This is not practical with an oil lens.

[Alexander]

Any idea why? Due to the worry of crushing the slide? That fear at least I can largely ignore. I use mine with oil many times when I use it.

Many oil immersion objectives feature a free working distance barely more or even less than the thickness of a standard cover-slip. This is why so many immersion objectives are designed for use without a cover-slip. The attempt to focus frequently leads into crashing the objective into the specimen. If your specimen is covered and the mount is too thick this will happen for sure. Diatoms for example are typically brought onto the cover-slip and then mounted to make sure the specimen is high up in the mounting media and within the reach of strong immersion objectives.

[charlie g]

Hi, Alexander and all. I did not say: 'never use an oil-objective on a 'permanent slide'...I said: 'understand that slides thickness, understand your oil-objectives working distance...see if the slide is compatible with an oil-objective.

Sometimes the border sealant on slides are too thick and you may drift into a crash horizontally, sometimes the entire slide is too thick...vertical crash.

I indeed use oil-objectives on the many compatible slides, many slides I have are too thick, and sadly I vertical crashed/ cracked a cherished diatom slide a UK microscopist sent to me. charlie g

[N3ptune]

Thanks for the info here, to be tested in the next days.

[BramHuntingNematodes]

i give the lens tip a single swipe with a kim wipe after im done and thats it hope im not doing it wrong

[Leitzcycler]

I use heptane.

My Leitz Orthoplan manual suggests using xylene, which is not recommended nowadays for safety reasons. It is rather nasty-smelling anyway.

[microcosmos]

I just read an interesting paragraph on Nikon MicroscopyU about an unexpected positive effect of not thoroughly cleaning immersion oil when using heated objectives for live-cell imaging, especially on inverted microscopes where the oil can flow downwards onto the objective barrel:

"The only negative effect of heating microscope objectives is that the retraction stopper barrel lubricant can increase in viscosity (achieving the pliability of gum) over a shorter period of time than with objectives that are not heated. However, in the case of heated immersion objectives, the tendency of immersion oil to creep into the barrel often prolongs the lifetime of the original lubricants."

Source: https://www.microscopyu.com/application ... cope-stage

[Greg Howald]

Everclear is 95 percent ethanol. It is what I use.

[Hobbyst46]

Excuse very late response.
1. KimWipes and lens tissue were originally recommended not because they are softer than (toilet paper, say) but because they do not release fiber residues.
2. About using immersion oil objectives on diatom slides, here is a conjecture: resin-mounted diatoms are not that mechanically stable. The resin might be extremely viscous, yet not really solid, and soft. The downward pressure transmitted from the objective through the oil drop, while certainly very low from ordinary daily events perspective, migh suffice to flex the coverslip and push the diatoms, which in turn might dislocate. Just a possibility.
3. To remove oil, it is best to use a liquid that easily dissolves oil. Methanol does not. Ethanol - a better (especially if pure, 95% or better), but not perfect sovent.
IPA is better than ethanol. Heptane, xylene are excellent, although the latter is more of a health issue. Acetone is excellent but should be avoided because it is too volatile and can dissolve cements in the microscope.

[MWK]

It seems the more I read about this the more I get confused... Why isn't there a straight answer to this question? Toilet paper? I would never use toilet paper, but is that because the purists convinced me that would be an awful idea or is there some truth to it?

Is there an ideal solvent that works generally well for all applications? As a hobbyist, I just need a simple go to solution that I can trust. I have 99.9% IPA + kimwipes for general optics and Sparkle + cotton swabs for my objectives, should I just stick with that?

[dtsh]

It seems the more I read about this the more I get confused... Why isn't there a straight answer to this question? Toilet paper? I would never use toilet paper, but is that because the purists convinced me that would be an awful idea or is there some truth to it?

Is there an ideal solvent that works generally well for all applications? As a hobbyist, I just need a simple go to solution that I can trust. I have 99.9% IPA + kimwipes for general optics and Sparkle + cotton swabs for my objectives, should I just stick with that?

I think the concern with TP is that it might have silicates in it since the intended pupose doesn't require the finest of fibers, but I honestly don't know if that's a valid concern or not. I use kimwipes and 70% IPA for most stuff, occasionally taking a slide to the sink for some soap if it's really messy.
It looks to me like "Sparkle" is distilled water, IPA, ammonia, and a colorant (https://www.advantagechemical.com/produ ... rkle-glass) so assuming no issues with ammonia or the colorant, if that works for you I'd stick with it.

The main concerns, as I understand them, are avoiding abrasives in the wipes (silicates, etc) and chemicals which will attack the mountant between lens groups, coatings, or the like. Got those covered and using a good technique to avoid dragging any debris removed across the lens and you should be golden.

[MWK]

Thanks for the reply, makes me feel OK about what I'm currently doing, haha!

To clarify, I meant this 'Sparkle' (https://www.globalindustrial.com/p/amsc ... ns-cleaner). Not sure what's in it though. No Ammonia for sure though.