i don't know about isopropynol per se, but its what we use in the laboratory (and we have isoprop). i believe it's because of how volatile 99% alcohol is. it would evaporate from the surface before killing most of the bacteria. Like i said there are disinfectant sprays out there that are contact dependent, such as lysol, which contain all the necessary ingredients to kill most of the bacteria. As for the fungal spores. If you happen to get a fungal infection from your pads, i would suggest just buying a new pair of guards. certain products may claim to kill them, but i wouldn't take their word for it. starskie, hows this: http://www.homesolutionsstore.com/cgi-bin/item/RB79329 would that do the trick? It says for hard non-porous surfaces though... would that matter?