I use peat moss and so do a good bit of other people, and it doesn't stink, and doesn't mold. I use a plain untreated potting soil for my plants and top them with peat moss, and i also have a full peat moss laying bin for her when she needs to lay in there for future use. no mold issues, but mold is caused by stagnant water be it a super high humidity, or the more likely culprit soggy moss. check the moss underneath, and see if its soggy if it is take it all out lay it on some screen, and let it dry in the sun for a few days, or go to wally world but a big thing of moss for like 7.86 and throw the old away (thats what i would do) make sure you sift it to get out any large debris like sticks ect. you just have to make sure the moss can dry out between mistings