I have a rice cooker and will try to disinfect a used mask when said mask is deemed germy enough. A coworker has tried it. Her advice: Don’t add any water!
Seriously though, if the mask is inside a vacuum seal, and you keep the mask out of the Sous vide device’s water jet, the water bath should provide a much more steady temperature, one which you have direct control.
With the rice cooker, often you have no control of how the rice cooker managers it’s temperature.
Throw in a couple of steaks or pork shops while you are bathing your masks, and you get to enjoy a meal and a clean masks after a couple of hours.
If you follow the instructions from the link I provided above, the rice cooker will automatically shut off after 3 minutes cooking, provided that you don’t add any water.
That is true for the most common rice cookers out there in Taiwan, however, not all rice cookers use the same mechanics, and some using the same mechanics have different settings so it might have too high a temperature.
The concept is simple, use a high enough temperature for a long enough duration to kill the virus, but not too high to avoid damaging the mask. So finding a device that allows you to set a steady temperature and duration seems pretty intuitive.
I personally don’t recommend it. Air-dry in the sun might be best. Or UV sterilisation . Actually best to throw it out. For cloth masks I would wash them.