Stay away from products that has any "grit" it in. We remove stains from our sinks by pouring Clorox Clean Up on it and just let it soak for a while. Has removed stains these past 6 years.
Bill B. (S.E. Michigan)
2014 Keystone Cougar High Country 321RES (was 2007 Eagle 322FKS)
2007 Dodge Megacab CTD