How to keep a white plastic yoyo white...?

I got a white Atmosphere recently and had just a couple of questions.

First, the white plastic is showing very slight signs of discoloration where it makes contact with my fingers - is wearing a glove the only way to prevent this? Also, is there anything I can use to clean it that won’t hurt the plastic or the metal?

Second, I want to take a cap off for IRGs. Does it pop right off with a suction cup like other YYJs do? Is there any chance of it rattling and not being as smooth if I were to put the cap back in later?