I know this has probably been covered extensively but the search engine is down. I just need to primer my rear bumper and i'm not sure what to use to strip the paint and/or prep it for primer. So any help would be appreciated. Thanks.

 

if it's already got paint on it you need to sand out all the imperfections with 220 grit. i would use a da sander on it. then blow some flexible primer (available at autozone or whathaveu) on the spots where you broken through to raw plastic. then sand it all with some 400 and paint it.