There are many fibers from clothing in a person’s belly button. Many of these fibers are synthetic and not biodegradable. They make up a large portion of the world’s microplastics problem. They will end up in the oceans and will be eaten by fish, which we will eat as well.
The microscopic fibers look quite beautiful under the microscope, especially in polarized light. I am using two linear polarizing filters, one placed over the lamp and the other one above the slide. The microscope objectives used were 4x and 10x.