In that other mold thread, I'm liking the idea about pre-treating mold with UV.
Then we need to figure out a good modification of a worthless Goodwill VCR. Preferably a model with a slower RAW/FF than not. I don't want to handwind, but I also don't need it to snap in one of those jet engine models of the late 90s and early 00s (made for impatient people, remember "Be kind, rewind!" ... or Blockbuster will charge a rewind fee!).
We also have an Israeli gas mask that I use for stuff like this.
Youtube how-to's are made by morons, and there's never been a good consensus method online for moldy VHS. But I think we're finally getting one together on this site this year.