Walterjn Yes we always used to close the door to the washer (front loader) and it wouldn't get to air out and the gasket gets moldy. By the time we started leaving it open the gasket seal was black. I couldn't make a dent in it with any regular cleaners, but this gel cleaned it up quite a bit.
I'd like to replace the gasket, but the dryer is mounted on top of the washer and replacing the gasket without taking the top off the washer looks to be a huge pain. The leak is literally just a drip every so often so a paper towel would catch it. If it really starts leaking or if they just die I'll replace them as they are older appliances. Both have lasted more than twice as long as our refrigerator and dishwasher.