If you want an effective means to disinfect a sponge, it's not unreasonable to turn to the standard for sterilizing intravenous infusion fluids (pharmaceutical

If you want an effective means to disinfect a sponge, it's not unreasonable to turn to the standard for sterilizing intravenous infusion fluids (pharmaceutical grade sterilization) back in the 1980s. That was designed to reduce a bacterial titre of 1 million organisms per ml down to one organism surviving per million litres, in other words by 15 orders of magnitude. And you can achieve this in your own kitchen quite easily. The trick is to use saturated steam at 1 bar overpressure — a pressure cooker at 15 psi will do this — for 15-20 minutes. (Pharmaceutical grade autoclaves are just pressure cookers that operate on a large scale.) 1 bar overpressure corresponds to saturated steam at a temperature of 121 degrees celsius and it makes a real mess out of anything with a cell wall or proteins. This is a whole lot more effective than merely boiling your sponges at standard atmospheric pressure, let alone the microwave-and-pray method. (Note: I'm going from third-of-a-century-old memory of pharmaceutical manufacturing standards here, rather than an actual citable source. Confirming it is an exercise for the reader and actual specifics may vary. A sterilized sponge, no matter how thoroughly boiled, may still contain residual toxic compounds left from bacterial decomposition. And as I allowed my professional registration as a pharmacist to lapse a long time ago this is not professional advice.)