Companies that refurbish phones use specialized chemicals and machines for renewing cruddy old phones.
Amateurs don't have to make a major investment, because most people already have two very effective chemicals in their bathroom.
- Rubbing alcohol is almost a universal solvent, very effective of cleaning off ink, label adhesive, and all kinds of goo from phone bodies and handsets. It's also good for cleaning cords.
- Toothpaste does a good job at polishing out minor scratches and dull spots. You can apply it with a toothbrush, rag or fingertip.
If alcohol doesn't remove the sticky stuff from your phone,
Goo Gone probably will. The new spray-gel is easier to work with because it stays where sprayed and doesn't drip onto nearby surfaces. You can get it from Grainger, Amazon and other sources.
If you want to give your phone a good shine, get out of the john and go to your garage, and get some
The Novus brand of scratch removers and cleaners is excellent, available from Amazon and other sources. Don't expect a quick miracles, but you can get very good results if you have patience.
If your hands get tired, it's tempting to try an electric rotary tool, such as a Dremel. Even at their lowest speed, Dremels may heat and melt the plastic,
so BE CAREFUL. You may be able to find something slower. A speed of 1,000 RPM is recommended, with a clean cloth buffing pad. Don't apply a lot of pressure. Be prepared to take some time.
Use cleaning chemicals sparingly, and don't get anything wet on the phone guts.