Toss em and buy synthetic? Seriously, are you sure that it isn’t dead and you are seeing the leftovers? You hit it pretty hard.
I guess the next thing would be to boil them, 20 minutes at 100C is supposed to kill most anything. The problems with molds is they grow from spores that can be really tough. Oak is porus, so spores could hide easily. Did it spread to the bungholes? Or just on the outside. I have seen bungs in Europe covered in mold on the outside, wet cellars. Didn’t seem to worry anyone.
Thanks! I am pretty sure it’s still alive so will resort to the boiling.
There is some mold on the bunholes but it is very manageable.
Love the comment about the Europeans not giving a crap about some mold on the bungs (European myself)