AAAHHHH DO NOT WIPE DOWN THE HUMIDOR WITH BLEACH!!! unless you want to throw that away too.
I'd just wipe the mold off with a rag and leave it at that. If you want to take it a step further, open up the humi (if possible) and replace the oasis foam. Even further, toss them and get new ones. BUT DO NOT WIPE THE HUMI WITH BLEACH.
If you keep your humidity in check (65%-75%) you shouldn't have any problems with mold.