I open the envelopes of any mail I receive outside, sanitize my hands to pull out the inside and immediately dispose of the envelopes. (My recycling bin and a thing of hand sanitizer are in my garage.) For the cards I have been mailing, I buy packaged cards, wash my hands carefully before writing, and use my dampened thumb to seal them. So there may be germs on the outside (but there always have been), but the inside is as safe as I can make it! :-)