For the bumpers you can try wet sanding with fine sand paper. you can also sand the door a LITTLE if the scratches are not too deep.
on the other hand you can also use scratch out. if the scratches arent too deep.
for the bumper. if the scratches are deep. make them smooth and on a level with sanding and if the paint is of SUItable color you can yourself paint yourself with spray paint. and if you are skilled the difference wont be that much.
I did this on my car WHITE and difference was negligible.