My husband passed away leaving behind a lot of unopened generic medical supplies such as gauze pads, rolls of blue tape like lab techs put on after blood tests, and a bunch of other stuff. Can Salvation Army accept/sell/give away these items?

I'm sorry to hear about your husband. There's a good chance these products would be thrown away. I would recommend giving them to a health clinic or an outreach for the homeless medical program. I gave a bunch of medical supplies to a woman in San Jose who worked in a free clinic in SF.

There is a donation warehouse in San Leandro for all medical supplies, that third world countries can request via their website. https://www.medshare.org/

The Salvation Army cannot accept any medical items. Look into Doctors Without Borders. Or any neighborhood clinics might accept them.