Unclear. I am part of the MIT+Harvard+Boston General initiative on REUSE of masks. Log reduction of pathogens though limited heat (dry or moist) is VERY unclear. Then, if you don't control very precisely the heat, their filtration capabilities are toast. I would ABSOLUTELY NOT recommend using an oven. At this point, heat might be a decontamination option, but early results indicates that duration will be long (18 hours) under precisely controlled temperature (like 70C).