Alright here's how its done....HOWEVER make sure you want to do this first cause I thought i did a year or so ago and now I hate myself for wasting my time and making my shit look ricer as hell. Now, i have stripped the paint of my interior/replaced parts/ painted some flat black to get the damn ricer look off....
Ok though enough of my complaints at myself, here's how to make it come out well....First, to answer your question, sand out the scratches if possible, if not replace parts. . .Ok...now...sand all parts you want to paint with a sandpaper which is not very course, you do not want to make scratches just scuff, then shootem with water, then rub them down with turpintine or paint thinner to take off any oils or dirt which may still be on the items, then wash them of real real well and let dry, then spary them with the first couple passes real light then you can get heavier until the piece is completly painted, and them let them dry overnight, don't try to put them in partially wet, for paint, i recommend rustoleum, don't waste your money on the paint that says its for interiors, its just a waste of $$$