Sorry I didn't clarify this earlier, when I said "Flat Black" I meant the aerosol paint you can buy for about $1.25 at Walmart. You need to determine whether you want to get "Semi-flat" or "Ultra flat." The flatter a paint is the less it reflects light; the glossier paint is the more it reflect light. Therefore if you put "Semi-flat" on your "Ultra-flat" part, the area you touched up will stick out and shine more the the rest of the part. Any how, spray some flat black into a small plastic cup let the paint thicken for a while and brush some of the paint in there like your touching up a paint chip on the exterior with a fine brush, let it dry and repeat if desired.