This isn't for poop stains in diapers, but on clothes. I thought you guys might have some good suggestions.
It seems whenever #3 leaks out of his diaper, it stains the onesies. The only thing I have found that helps is to wash it immediately on 90` in the washer. With my other kids, I'd just wash/rinse it off by hand in the sink and it seemed to come off, if it were a bad one, I would scrub it some with a scrub brush, but his stuff does not seem to come out. He is still just bf.
Washing it at 90 isn't such a problem, but I feel like it is a waste to throw one onesie in a load (we have no s,m,l adjuster, just one size). If I keep the onesies in a wet bucket, until I have a white load, that doesn't help either.
Dare I ask what #3 is?
My daughter has always had very "stainy" poop. I would advise you to rinse it in the sink asap, spray with Bac Out and then wash as soon as you can. I've heard washing on warm is good for poop stains but I've also heard cold. I think washing it sooner rather than later is more important than the temp, as long as you are not washing it in hot water. (For the record, I've never been able to tell a difference between washing in warm or cold as far as stains go.) After it's washed, if there is still a stain then lay it out in full sun for a few hours. If it dries quickly, spray it with a spray bottle to keep the stain wet so the sun can do it's job. The sun is the ONLY reason I was able to get my DD's stains out of her clothes when we had the occasional blowout. Thankfully, cloth really did save us from having too many. Most happened if she was in a sposie.
When DS was in disposable diapers and pooped out of them I would rinse out and then soak in oxyclean. I then would wash with regular laundry later. Also sunning can help a lot! I sun DS's diapers all the time and it makes a big difference. I'm sure it would have helped tremendously with clothes too.