Why do my black plastic frames turn white?

March 23, 2009 6:05 PM

My glasses have black plastic frames and they turn white when wet from water or sweat, how can I get them clean?

I initially thought this was from sweat because I first noticed it after going to the gym, but my bright idea of washing the glasses to get the sweat off exacerbated the problem. It basically looks like the plastic itself has turned whitish. They eventually (after a few days) turn black again, but I have no clue what makes them return to their normal color. Any suggestions to either prevent this or to clean them (as well as scientific explanations as to why this happens) would be much appreciated, thanks!

posted by BugsPotter to clothing, beauty, & fashion (2 comments total)

I have seen plastic do this, but I can't remember what kind. Eyeglass plastic shouldn't do it. I would guess that water gets absorbed into the plastic and changes the shape of the plastic not unlike the way plastic turns white when you bend it but then clears up when you return it back to shape.

Or, it's dirt/oxidation that has built up on the glasses that gets waterlogged and turns whiteish, but then dries out again.

Try polishing an inconspicuous area with something like 3M Plastic Polish (get it at the auto parts store, it's probably $6). See if that makes it worse or better. I'd bet it makes it better. If it does, you might even consider waxing them with a product that blocks UV that's made for plastic. (Probably the auto parts store again...)

(Thanks Jebus once again for the invention of contact lenses...)
posted by gjc at 6:48 PM on March 23

I bet the plastic is getting slightly porous and the newly-exposed rougher surface doesn't look black any more- think of how beach glass turns whitish when dry, but intensifies in colour if it's wet. Similarly, I'd guess the white fades back to black as a thin layer of oil from your skin and hair soaks into and smoothes out the surface of the plastic again. A dab of olive oil rubbed into the plastic with a tissue might help (test somewhere inconspicuous first, in case I'm wrong!). Or just return them to the store and maybe you can get a new pair.
posted by pseudostrabismus at 10:32 PM on March 23