An article from Consolidated Sterilizer Systems starts with: “With the global Covid-19 pandemic everywhere in the news, many healthcare professionals and concerned citizens are grappling with the shortage of respirator masks, vital tools for ensuring that healthcare workers are not infected by the people they’re trying to help.”
The article suggests that microwave steam based disinfection has been effective at disinfecting, specifically removing H1N1, from non-metal N95 respirator masks. Here is a 3D grid that can be placed into a glass tupperware container filled with some water and then put into a microwave. Don’t put anything with metal into the microwave. Alternatively, you can use this grid in the oven as well; see the description in the article.
This grid is 4.4" square and 1.25" tall. It’s easy for me to produce any other dimensions.
The log reduction for microwave steam is around ~5, i.e. 100,000 times less viable virus. The article does not give a protocol. I put the filter in the microwave for 3 minutes which was sufficient to boil the water for 2 minutes. For oven steam, the protocol requires 3 hours under warm water steam and let to a slightly smaller log reduction of ~4.8, i.e. 63,000 times less viable virus. This requires an oven that has good temperature control.
Disclaimer: It is unclear if this is effective for disinfection. Even with high-temperature filament, it is unclear if a 3d printed grid is appropriate for this application.