Try a cleaner wax. The solvents will generally cut the rubber without harming the finish. If that doesn't work, try a light polishing compound. If that doesn't do it, try a bug and tar remover.
Rusty
2014.5 DRV Mobile Suites 38RSSA #6972
2016 Ram 3500 Dually Longhorn Crew Cab Long Bed, 4x4, 385/900 Cummins, Aisin AS69RC, 4.10, 39K+ GCWR, 30K+ trailer tow rating, 14K GVWR
B&W RVK3600