Fine scratches on Kohler sink
We just completed our new home (YEA!!!!!!) and I've already noticed quite a few very fine scratches on the bottom of my Kohler sink. It is cast iron (with porcelain on top?). I have only been cleaning it with a few squirts of dish soap and a scrubber brush. The brush is new, so the bristles are not hard, but are firm. Could this really be the cause of the scratches?? I find it hard to believe that a scrubber brush would do that to cast iron! It's not like I'm just bearing down on it, I thought I was being quite gentle! Any help would be greatly appreciated. For what it's worth, the sink is black -n-tan, (kind of a specialty/designer finish) but wasn't supposed to be "delicate".