Hahaha, we had this problem and the interwebs gave us the 50% Dawn + 50% Vinegar + Heat formula. Mix, heat, spray, let soak, then rinse. Problem is it's waaaaaaay too much Dawn. Total pain in the ass to rinse off. I would try it again with about a 10% Dawn to 90% vinegar ratio, 20/80 at most. The purpose of the Dawn is partly to cut through greasy residue, but mostly to hold the vinegar in place long eough to work its magic. Pretty sure less Dawn will result in less cussing, too.