ducky

So i think i've got some road tar on my rims..all 4 of them..didnt know when this happened..i brought it back to the dealership and they said it might be road tar as well..i was gonna powdercoat the rims black anyway..but the guy charging me $600 for all 4 rims which i thought is kinda pricey..
My question is what is a good product out there that i can use to get rid of the road tar stain on the rims? did i mention it basically smooth itself onto the rims as well..any help is appreciated..thanks