Sunglasses have a soft plastic label on their lenses. After the trademark is removed, the place where the trademark is affixed is slightly lighter in color than other places. How should I remove this mark? I used to sell sunglasses. To answer your question, long-term exposure to ultraviolet rays, or long-term exposure to high temperatures or places with high temperatures (such as counters with small spotlights) will cause this phenomenon, which can't be eliminated in general. Unless you change the lenses, you are a resin sheet. Don't base the lenses on water for a long time, which will deform the lenses and avoid contact with alcohol. Alcohol is a taboo!