We have a front load washer and the rubber ring door seal has mold on it. Where it is has turned that portion of the seal black. I have scrubbed it with a green scrubby pad and bleach, but the black doesn't come off. It appears to have permanently discolored the rubber. I'm wondering if scrubbing it with the bleach would have killed off the active part of the mold, the part that's bad for us, and the black that's still there is now just a harmless stain.