Anybody's MBP suffers from decolouration due to old age and long usage at the palm rest and keyboard area? I just want to confirm, because if there is, I will buy some protectors to go over.
yes, some people report that their palm rests become shiny
Use windex and a paper towel every few weeks. No need for a shield.
Windex is a bad idea. It can be damaging to the aluminum. If the OP really wants to, he can buy some iklear to use, but a damp cloth is really all it takes to clean the exterior.