With so many products using plastic---cell phones and MP3 players, windows and tabletops---an entire genre of scratch removal products has evolved. People use automotive rubbing compound, sand paper, toothpaste and specially formulated scratch removers to remove scratches. But consider the size and use of the piece when choosing the application. Many electronic devices with plastic faces can be ruined if subjected to moisture and some compounds create more scratches. Consider a few milder ways to remove light scratches from clear plastic.
Clean the surface before applying scratch remover or compounding products, to remove any specks of dirt and grime that could further scratch the surface. If the item can get wet, use a mild soap and water to clean it. Lightly pat dry with an old T-shirt or rag that won't leave fluff. If you're cleaning the cover on an item that cannot be submerged in water, squirt window cleaner on the rag and carefully wipe the surface.
Start with a very light abrasive cleaner such as furniture polish. Spray the polish on the plastic surface and buff it vigorously for at least three minutes. Scratches can be buffed out with plain soapy water. Exert gentle pressure as you move the cloth back and forth quickly across the surface.
Use a more abrasive scratch removing material for remaining scratches. White toothpaste and mild automotive rubbing compounds that don't have any crystals or other heavily abrasive materials in them work well on light scratches. Squeeze a small amount over the scratch and rub it in with your finger in small circular motions. Allow the substance to dry for about five minutes and rinse or wipe it off. Soft Scrub works in the same way on clear plastic surfaces with slightly deeper scratches.
Find products made especially for clear plastic when other remedies fail. A line made by Meguiar's that works on stubbrom scratches is Mirror Glaze Plastic Cleaner. It comes in a lotion and is easily rubbed into the surface with a clean cloth, left to dry and buffed off. Follow with Meguiar's Mirror Glaze Plastic Polish to keep the plastic free of dust. Other products that work well on plastic include those produced by Janvil and Diamondite.
Bring in heavier equipment for deep scratches. Very fine wet/dry 120 to 160-grit sandpaper can be used to recondition a piece of plastic marred with scratches. Wet the sandpaper and rub it in circular motions very lightly over the entire surface, rinse before it has a chance to dry. Buff the surface with a clean, smooth buffing wheel to bring out the natural sheen of the plastic.
Start with the least abrasive product first. If the scratches are still there, then move up to the next most abrasive technique. Professional polishers always clean plastic in phases.
Never use acetate-based products or lacquer thinner on plastic because it will permanently melt the material.