I got a set of nylon polishing wheels at Christmas, today was my first time using them but I'm finding even the finest grade leaves very deep scratches in aluminium. I've hit it with wet and dry but I'm going to be going for an eternity and a shopfull of it to get the scratches out, is that quite normal and I just need to knuckle down to it or have I got a set that is missing the finer grade? I'd read on here that they are great for doing rims but these would leave a terrible mess.