 Like I said, I've used it myself. I found it on the Internet one day and tried it and cured the problem of exactly what they say. On the washer, you just put a little dab, goes in there, I mean, like a teaspoon. And you ran water, ran a cycle with no clothes in it, of course. And the black gunk that it flushes out, the biofilm back in the closed plumbing system, it's amazing how it disinfects that and eliminated the smell.