I have a friend that owns a mold remediation company and has mentioned blasting with dry ice and some type of non-abrasive sponges. He has also mentioned using chlorine dioxide to fog a building and has a colleague in Florida that uses chlorine dioxide for mold remediation.
I’ve done a fair bit of mould remediation. Dry ice does work well, but the only time we actually used it was after a fire to clean soot off exposed framing and the attic. It was a little pricey (any mould remediation is), but does a better job in a lot shorter time than scrubbing/sanding by hand.