How to clean old slides?

[Milou]

Hello,
I've got some slides boxes which seems quite old and have kind of white spots very difficult to remove...
These ones have never been used and some are bonded together in their original carton box

I've tried first with warm water and dishwashing liquid but not very effective...

I also used isopropyl alcohol 99%, white vinegar, but still not got a perfectly transparent slide....

Anybody have an idea about other ways (perhaps hydrochloric acid?) to clean them?

[Phill Brown]

I have some old 3"x 2" slides where the surface is degraded. Looks like white residue but somehow the surface is eroded in patches,
Worth checking by reflecting light at an angle across the surface with good magnification.

[Milou]

In fact I checked under binocular microscope these slides and they have a kind of white coating, which can be removed when scratching the surface with a needle !
But I don't know how to remove it

[MicroBob]

The hydrolysis resistance of slides glass is low. They attract humidity and the surface is damaged permanently. This can happen quite fast and hits mostly unused sildes closely packed in boxes, not prepared slides in boxes where they are held apart from each other. They can't be cleaned unfortunately.

[Hobbyst46]

The hydrolysis resistance of slides glass is low. They attract humidity and the surface is damaged permanently. This can happen quite fast and hits mostly unused sildes closely packed in boxes, not prepared slides in boxes where they are held apart from each other. They can't be cleaned unfortunately.

Exactly the same experience here. Even if they were originally good quality, poor (for long range) packing in the box has its toll.