stains on truck finish

Dummy me, decorated my dad's truck for Fourth of July parade when it was raining lightly, and now the blue crepe paper left a light stain on the body paint of the tailgate. There are also red crepe paper stains on the plastic bumper. Any ideas to clean it up with out ruining the finish?

I'd start with a cleaner wax product and advance to a scratch remover if that doesn't work.