I used the curved end of a Standard Hive Tool to scrape off most of the black mold. This was followed by spraying 3% concentration hydrogen peroxide, waiting 10 minutes, then wiping off the mold with a cotton rag. Shown is the migratory cover after cleanup, ACE hardware spray bottle and CVS hydrogen peroxide. I found the cleanup steps on THE MAIDS BLOG.
I wore rubber kitchen gloves and safety glasses for the hydrogen peroxide portion of the cleanup.