Stripping paint off of urethane bumper?

[76L82]

My 76's rear bumper is a complete mess. The paint had obviously flaked off in multiple locations and "Bubba" took a grinder to it and it looks like he literally burnt the paint and or the urethane in some locations. To follow up, he spray canned painted it.

Is there a way to strip the paint off without 'dissolving' the bumper? Could a sander, if used probably, do the job?

Thanks for the help.