2 way to clean plastic,
First one before i even start sanding or anyithing, wash model in dish detergent and water. with a good rinse.....
2nd, after sanding and stuff?
I will take the same stuff that my paint thinner is made of after giving a nice top coat of paint, and wipe down the model.... let dry for about 2 hours, then I will wash off with pure water, then just before painting a 2nd top coat, i will use a tack cloth (for a general wipe down)and also use my airbrush(for a general air spray down) with no paint in the airbrush and spray off the model, and then RIGHT BEFORE I paint the model i put it up, away from my paint chamber , I will use a simple "misting bottle" AFTER I have spayed and thoroughly clean my paint chamber, and mist my (spray area, paint chamber), and then spray paint, if I want that GOOD of a finish, if i am spraying battle tanks or whatever, I don't bother with all that, I just spay the "crap" on there. Tanks are supposed to LOOK painted.... Cars, well, You can spend a million bucks on a finish for a car, but they can still be crushed by tanks