I recently discovered that my brilliant idea to store all my reed boxes on the picture molding in my room was not such a brilliant idea when some (interestingly, not all) of the boxes of reeds got some mold on them. I wasn't ready to throw away almost two hundred dollars worth of reeds, many unplayed, so I did peroxide soaks on all of them over the course of a couple of days. I forget the exact concentration, but it was fairly diluted. I soaked each batch for about 10 or 15 minutes, then pulled them out, rinsed them with plain water, wiped off the excess with a cotton cloth (actually just a t-shirt) and left them out to dry. Thankfully I caught the issue before the mold got really bad, so it was limited to some small spots on the reeds most of which came out when I wiped with the cloth. A couple didn't come off and I threw those away. I have a mold allergy that isn't severe but is enough to be noticeable if I use a reed that is a little questionable and this technique seemed to work pretty well for me.
I have moved to synthetic on some horns, which is nice, but on the ones where I can't make synthetics work, I now use the D'Addario reed case with the little slot for the Boveda humidifier packets. It's not terribly expensive and it really does seem to regulate humidity enough that the reeds are reasonably stable (until I do crazy destabilizing things like play on them) and don't stay wet enough to cultivate mold.