how do I clean mold off a vinyl doll?

Clorox mold and mildew spray

Pour undiluted white vinegar into a spray bottle. Because white vinegar contains only about 20% acetic acid, adding water makes it less effective. Spray the vinegar onto the moldy surface and leave for an hour. Finally, wipe the area clean with water and allow the surface to dry.

If you don't care to be smelling the odor of the vinegar, then try using Lysol Spray. The non scented kind. Lysol also kills mold and disinfects.

i would just get rid of it and buy another one