Re: Late extraction, moldy comb
Is your basement dry. Possibly some minerals that deposited on the outside of the wax as moisture was driven off from evaporation. Without the bees present to keep the comb clean it could be anything. If you didn't get that much I have to ask why you took it off early? Wouldn't that put your bees at risk?
BTW I put moldy frames from a dead out in a new hive and the bees cleaned it up and used it like it was new.
Zone 5a, Practicing non-intervention beekeeping