From the last thread - That’s an idea. Run an iron over the mail. Not on those little plastic address windows though.
I put my mail in the toaster oven. 200 degrees for 10 minutes. Mail comes out toasty warm. The plastic melts a little bit.
Seriously. Burning point of paper is 400 degrees (except the first time I did it I forgot about the plastic - but not a bid deal.) Most viruses are destroyed at 5 minutes or something at 180 degrees. I know my 200 at 10 was above the limits by a slight amount.