So, I have a set of Norton's. The two combo stones give me the 4 grits offered by Norton. I really don't have any issue with these stones and I can hone well enough that the shave is comfortable.

About 4 months ago I tried to hone one of my razors and the test shave was less than stellar. The problem is I ran out of time, so I set the razor and hones down to come back the next day or later that week. The hones sat in a tupperware full of water with a rag between them so they didn't bump or grind.

I pulled out the razor today thinking 'I am going to fix that razor'. To my horror the rag between the rags was black. Also, the side of each hone that touched the rag was black. Mold had somehow grown in the tupperware.

I have lapped the hones but in some places it is still black. Any thoughts on how to get rid of it totally?