I have mineral build-up in my toilet bowl, every where the water flows into the bowl from just under the rim. I have tried everything I can find that states it will clean hard water and mineral stains. I think "stains" is the key word leading to why the products don't seem to work for me. I can actually feel the "build-up" when I rub my finger across the discolored places. The only thing I have found that will temporarily remove the build-up is lava-stone (can't remember the real name of the stone). However, it also scratches and mars the bowl's shiny finish so that it looks almost as bad just after I have removed the build-up as it did before. I am going to try CLR again, but I think I have tried it before and it didn't work either. Any body else got any suggestions? Thanks.