Are hands considered impure after touching a tissue contaminated with washings from a doorknob and the edges of a toilet, and what is the ruling on everything touched thereafter? And does the ruling transfer to a brother's hair that was touched after the swimming pool? And what is the ruling on purifying contaminated items in a car with sun, dryness, and wind?

"Waswasah" (whispers/obsessive thoughts) is one of the most dangerous diseases that can afflict a person. Its cure lies in ignoring it and not paying any attention to it. The basic principle regarding things is purity, and nothing is judged to be impure except with certainty. If there is certainty about its impurity, then the transfer of that impurity is not judged except with certainty of contact. The change in the color of a swimming pool due to dirt does not make it impure.