After reading through most protecting tips... I decided to replace one of my keys that has been wearing down quite a bit. Considering I've only used the same one for the last 4 yrs, it's been doing OK.
Here's what I got:
check it
Not awful, but slightly annoying. Thing is, if ANY part of this key is going to show wear, it will be that face plate. It's a thin aluminum that would certainly scratch and damage before anything else.
The rest of the key is still perfect. Not a mark on it.
It is a good place to try if you also want to protect you key well!