Had this stuff around for cleaning a moldy shower; never thought to try it on laundry until I was brainstorming what to do about some mildewy towels that hadn't been handled by our washer water ozonator, or non-chlorine bleach. Read the label and found it had instructions for laundry so, used some to wash the towels that had been suffering lingering mildew odor for weeks and voila! Mildew gone.Also works great at dissolving oils (ring-around-the-collar, sheets, etc) so now all our linens are as fresh as the day we bought them. It can be a little rough on bright colors (think of those 'enzyme wash' jeans): Yes, the active ingredient in sporicidin is enzymes so use common sense (no silk, etc, etc) and spot test.Not only is it safe for septic systems but, they even recommend flushing some to keep your septic healthy. I use it in the toilet tanks to keep the iron bacteria at bay--yep, we live in the country with a well, and....MICE! Which leads to to the super job it did of decontaminating one of our cars which is parked outdoors that the deer mice had taken to infiltrating. Sprayed the vents, carpets, and door mats with a diluted mixture and when everything was dry--mouse smell: GONE. And they haven't been back even though we have some yummy peanut butter baited traps waiting for the first one who tries it...Anyway, all around great stuff. Oh, as for the moldy grout: It could not get all of the deep mold stains out (really grotty porous old grout in our last place which hopefully the landlords have re-tiled by now). But, for surface mold, it's quite effective.