This is an interesting question for a few reasons…. It’s pretty easy to get mold off the surface of a wall TOPICALLY…but is that really what you want to accomplish?
There are old habits in several markets across the USA in which contractors and handymen have chosen to cover up a mold issue rather than solving the growth issue for the whole structure. Often, mold will come back in a different spot. Sometimes when an issue has been manually cleaned off of a surface, the same thing can happen.
Spores from mold are released from the mycelium of the growth when they are disturbed, so basic cleaning actions can sometimes exacerbate an air quality issue, spreading mold around a home or building and resulting in growth somewhere else.
It’s important to consider getting professional help for this reason.
That said, if you have an isolated issue, have handled any humidity or causal contributors to the mold growth, and are not talking about trying to cosmetically repair an issue that should be repaired structurally, it IS possible to clean up mold off a surface pretty easily.
White vinegar, 409, NOT BLEACH…. Wet the surface thoroughly and let it sit for 5–15 minutes before attempting to wipe it up. Any highly acidic solution will do. Once you have wiped up the initial cosmetic issue, consider retreating the same area and the area surrounding the staining an additional time.
This DOES NOT resolve the air quality issue…just the topical issue of mold growth. Be careful to not clean up something larger than a few square feet by yourself. Attempting to clean up a large patch of mold that has been left to grow for a long period of time can result in growth elsewhere in your home and respiratory issues if you have too much exposure.
Be smart. Get a consultation from someone before you tackle a large project on your own.