Well I just tried a Power Wash cycle with a black comforter to see what would happen. I used hot water (which I’ve only been using with this powder), added a 1/4 cup of detergent, let the machine start filling with water, then added the comforter. I chose “regular” soil level and 2 rinses, deep water level. The comforter came out mostly free of residue, with the exception of a couple of minor specks. I do think they will come out in the dryer since they did in the dark pants in the previous load, on the “whites” cycle.
mrboilwash- it seems that using these different (power wash or whites) cycles, which have more agitation and I can choose the “deep” water wash, seems to be making the difference. When I was using the “normal” cycle (which automatically detects the water level for you and you can’t override it to “deep”), even with mixing it with hot water in a jug first, using hot water, adding the detergent first, reduced amount of detergent, 2 rinses, plus sometimes a rinse & spin afterwards, the amount of detergent left on the clothes was unacceptable. As in, large streaks and globs.
I do like the “normal” cycle because I don’t think it’s as hard on the clothes, but I’ll just have use that one with liquid detergent from now on.