You can use cleaner crews to help keep the substrate free of mold, fungus, mites, gnats and odors. I use A. diaperinus in dry substrate and Collembola in damp substrate. I also use Blaberidae "Kenya" with larger "moist" species like A. insignis and B. giganteus. Aside from that, I just hand pick any food remnants, exuviae and dead roaches — maybe stir up the substrate every once in awhile. As long it remains odor-free I typically don't do much cleaning... I do however spend a lot of time fussing and maintaining the aesthetics of my natural enclosures... lots of moving bark, swapping out branches, mixing in new leaves ... you know, the fun stuff. ?