How to clean my white plastic iPhone case? - 1

I bought an iPhone case online and it arrived a few days ago. It's a matte white plastic hard case. After a few days I've noticed that it's gone a bit pink/brown and is losing it's white colour. What is the best way to clean it? (preferably no strong chemicals, I've tried acetone polish remover and it started to wear down the plastic)

Remove the cover. Soap and warm water.

Or

Alcohol Based Lens Cleaner

or

rubbing alcohol