How to Get Rid of Mold with Plain White Vinegar.
Molly, I have had similar experiences in the past when my daughter nearly drowned some of my plants while on an extended vacation. Some of my pots were ceramic & some were terra cotta. This was a successful method for me .
As you have allergies, I would recommend donning a mask before you begin removal of the plants from the post & the cleaning process.
I removed the plants as gently as possible and laid them out in a sunny dry area on some newspaper -loosening some of the soil lightly in order to allow the roots to "breathe" a bit. Be careful not to handle or damage them any more than necessary.
The newspaper, as well as the sun, succeeded in removing some of the excess moisture; as the plants were otherwise in good condition this did not seem too harsh for them and did not appear to "stress" them..
I took the emptied pots and washed them thoroughly in mild detergent, then rinsed throughly in hot water. Afterwards, I poured 1 cup white vinegar (undiluted) into a plastic spray bottle. I took the pots outside to a sunny shelf and sprayed them thoroughly inside and out with the vinegar. I then allowed them to remain in the sun until dry, and repeated the process.
After the pots were once again dry, I added a appx 1/4" -1/2" small pebbles in the bottom of the pots and then some fresh dry(er) potting soil to fill around the roots of the plants as they were placed back in their original pots, carefully allowing some of the dampest soil to fall away from the roots.
The vinegar seemed to be the easiest and least expensive product for removing the mold. We had used it in the past to clean when we had a pipe break in the bathroom wall - The odor is strong but mostly airs out by the time the pots are dry.
We did not experience any problems with mold returning afterwards (SO FAR) - either in the bathroom or in the pots since the concrete, and the terra cotta were pourous and the vinegar was absorbed.
It was a very simple yet effective mold removal method without using harsh chemicals which may have succeeded only in making matters worse.