I have found that after cleaning, some car wax on all the plastics and the props works well. Just rub on. Wait 30 mins and buff off. I like to imagine it has some positive effect on the props by creating less drag. But I am sure the effects are negligible.
I use compressed air can for motors, as far as moving parts and inside i use a super soft fanned paint brush, skinny long one to make sure i get inside good,make sure it has white bristles and you'll be surprised at the dirt, i usually have to rinse it off a few times in between spraying it dry with air can.