That vinegar trick from Asheville is basically a hard reset for the scoby's pH. Honestly, I've seen it work on a pellicle that looked like a science project gone wrong. The key is that acidic environment just doesn't let the bad stuff get a foothold again.
Just do it with raw, unfiltered apple cider vinegar (the cloudy kind with the mother still in it) and only for a few seconds, otherwise you'll shock the whole thing into dormancy.