I soaked it in starsan to kill the mold, and washed it out afterwards, using pbw.
I got the brew hauler soaking in some starsan, will wash it out good later. I never intended to get rid of it, but that was my emotional state at the time... I was slightly disconcerted... StarSan isn't a very effective cleaner. Soap and water, Oxiclean, PBW, TSP, or anything like that will do a better job of cleaning than StarSan, so they would probably do a better job of reducing the bioburden.
I don't think that Starsan will effectively kill the mold without washing it first. Starsan works on clean surfaces, where the contamination is relatively rare and sparse cells, but won't necessarily penetrate into mold colonies. Soap will probably kill more of the mold than Starsan, in this case. Not that I would bother with the Starsan at all, but I just wanted to reinforce the practice of "clean, then
Something like 5% bleach would be very effective at killing the mold, and virtually sterilize ("decontaminate", technically, but almost nothing can survive 10-20' in 5-10% bleach). However, bleach and plastic aren't usually compatible, and I'd hate to see the Brew Hauler become brittle and snap.