The HIVirus dies thirty seconds to a minute after it leaves the body. Hope that clears that. Then, there has to be a way into the bloodstream. Like a cut, a tear, a puncture or a sore. There has to be a fluid HIGH in HIV for infection to occur. The fluids are, blood, semen and pre-cum, vaginal fluids and for babies, breast milk. This virus is very easy catch and also very difficult. All the right circumstances must be present for infection to occur. A fluid HIGH in HIV, a risk activity and way in will lead to transmission.
Never heard of a person infected through soap or towel although I have had a friend worry because she used my soap and braided my hair. It was in the late 90's. I have lived with AIDS for almost 15 years and I have done education and outreach about the virus for over 13 years.