I do my very best to judge no one who posts here and I'm not judging your friend but THAT is truly gross. It sounds like a bit of a psychological problem and as his friend, I'd tell him this directly. Collecting strangers dirty, discarded menstrual pads and tampons is something to talk to a professional about especially since you term it 'an addiction'. For the sake of HIV, since you've posted on the HIV forum, there is ZERO risk of HIV. HIV is transmitted in known and specific ways that include having unprotected (without condom) vaginal or anal intercourse or sharing IV needles to inject drugs with. That is it. Air inactivates the virus. Old dirty pads and tampons will not transmit HIV. STDs are not spread by handshakes, hugs, toilet seats, towels, dishes, telephone receivers, or insect bites. That list will include sanitary items.