[Andy from Chapel Hill]

You could try ozone.

Put them loosely in a big 3 mil garbage bag and put an ozone generator at the open end and then use big rubber bands to seal the bag around the generator and let it pump ozone in the bag for an hour or two. I doubt if anything will survive, but I am not an expert.

https://www.amazon.com/gp/product/B00DNHUZ0M/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

[LilFarmer]

Thanks for the tip, I‘ll look into that one.

[21twelve]

I use an ozone generator for the groceries and stuff. Let it run in the trunk for a half hour or more at 100 cubic feet / min. is probably overkill. After a few times it destroyed the elastic on the mask. So I just air dry the masks now for 3 to 4 days to destroy the virus. I bought a bunch of rubber bands for the masks - so replaced the elastic that I destroyed.