White discoloration on the frame of a pair of plastic eyeglasses results from the plastic reacting to acids and chemicals in perspiration, facial grease or cosmetics on the face of the person wearing the eyeglasses. Since any chemical strong enough to remove the discoloration from the frame will also damage the frame, the only solution is to use sandpaper to scrape off the white mark. You can do this yourself at home using some purchases from a home supply store.
Remove the screws holding the plastic frame to the lenses using the jeweler's screwdriver, and take out the lenses.
Hold the plastic frame in one hand. With the other hand, gently but firmly rub the 100 grit sandpaper against the white discoloration on the frame.
Repeat the process of rubbing the 100 grit sandpaper against the discoloration on the frame until most of the white has been removed.
Use the 200 grit sandpaper to rub gently but firmly against the remaining white discoloration on the plastic frame. Continue rubbing the discoloration until all of the white is gone.
Turn on the jewelry polishing wheel. Hold the plastic frame against the polishing wheel at the area where the white discoloration was. Remove the plastic frame from the polishing wheel once the plastic frame has been polished.
Reattach the plastic frame to the lenses by replacing the screws using the jeweler's screwdriver. Wipe off the plastic frames, which should now be free of the white discoloration, with a soft cloth.
Frequently inspect the progress of the sandpaper while using it to sand off the white discoloration. If you do not have access to a jewelry polishing wheel, try polishing the frames with a new nail buffer.
Too much pressure applied to the polishing wheel can damage the plastic frame.