Squirt liquid dish washing detergent into a bucket of hot water and mix the solution thoroughly.
Put on gloves and a face mask.
Open the access hatch to the metal roof. Where the access point is located depends on your model of mobile home. It is either located on the ceiling inside the trailer or through an access point on top of the home. Climb through the access point with the help of a ladder.
Use a flashlight, once inside, to see where the mold is located.
Scrub the metal surface with the detergent solution and a sponge to remove the mold from the surface. Scrub until all of the mold is removed.
Mix 1/2-cup of bleach with warm water in a bucket.
Climb back up into the attic and wipe down the metal surface with a sponge dipped in the bleach solution. This will disinfect the surface and prevent the mold from reappearing. Let the solution dry on the surface instead of wiping it off.