I've got a few PF tek jars fully colonised just waiting birth. I had one that had a distinct black mould infection. Instead of throwing it out I just left it to see what would happen. The mycelium actually grew over the mould completely and you cannot tell it was ever there now. Jar is now fully colonised. I will still likely throw it out as a precaution, but that was certainly interesting. No foul smells or anything. Mycelium is amazing.