Found this tips, perhaps it can be useful for you :
- Rubbing alcohol is the best to use on most of your phone (buttons, speaker area, etc) for getting rid of germs and oils, however on some older models that have the plastic encasement over the display you will want to use glass cleaner on that particular part or else the plastic covering may turn opaque.
- You may also want to occassionally clean the bottom where you connect the charger. For this, you can dip a soft bristled toothbrush in a bit of rubbing alcohol (do not immerse it) and gently brush the connection area to free up any goo or small particles that are wedged or blocking your connectors.
- Never use any type of liquid behind the battery. Most phone manufacturers have a dot or line on the back behind the battery that - if gotten even remotely wet or damp - will leave a tell-tale mark. It won't hurt your phone, but if you should have an issue while it is under warranty they will assume it is water damage and won't even bother taking it apart to see otherwise.
