The only experience I have with this is when I recharge my Purigen packs. The directions say to use a bleach/water solution and soak the pack in it until it's white again. Then, rinse until you can't small any bleach. Then, put the pack in a bowl of FW
and add some dechlorinator to remove any that might be left. I have done this several times with no bad results. I don't know about using the bleach on other types of filter media...some of them might absorb it. Bio-media should just be rinsed gently...preferably in tank water. Most other filter media is disposable and not worth the trouble to try to reuse. If you can be more specific about the product, someone else might have more input on this. The Purigen is the only thing I have ever used that wasn't disposable.