Got a confession to make about my toilet. When I restored the trailer, I did some maintenance on the old Aquamagic avocado-green plastic crapper. Part of that maintenance was cleaning the bowl because the PO had used it as a storage bin. I'm guessing he never used the Aquamagic for it's intended purpose as there were marks from tools and dirt in the bowl.
I ended up using rubbing compound to remove the scratches and polishing the inside and outside until it gleamed. Besides having to wear sunglasses when using it for it's intended purpose, it is working 100% with no wear marks.