I use the same stuff that I clean the bike with. It's called Miracle Wash and it is a waterless wash and polish. It works great on metal paint, plastic and glass.

Miracle Wash

It works really good on my helmets shield.

Tom

Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety. Benjamin Franklin, US author, diplomat, inventor, physicist, politician, & printer (1706 - 1790)