P.K.
Vinegar, and leave the washer lid open when it's not in use. BTW, I add vinegar during the wash cycle...there's no way I'm timing it to get back down there for the rinse cycle. However, if you have a bleach or fabric softener dispenser that you don't use, I suppose you could try adding the vinegar in there for a "timed release". I never thought about it...I just always added vinegar with the soap.