Vinegar and baking soda mixed with water works great for removing black mold from showers and other places.
Just place some white Vinegar and baking soda in a spray bottle mixed with water and then shake the spray bottle to mix up the baking soda and vinegar.
Then spray the mixture on the black mold and let it sit for around 15 minutes and then it should scrub off the mold.
The vinegar and baking soda will also kill the black mold as well.