Hand washing. Hand washing, also spelled handwashing and known as hand hygiene, is the act of cleaning one's hands for the purpose of removing soil, dirt, and microorganisms. This may be done with or without the use of water, other liquids, or soap.
Sunscreen does expire. The molecules in suntan lotion (such as homosalate and octyl salicylate) block the penetration of UV radiation by acting as filters and absorbing and reflecting high energy UV. Over time these molecules break down and lose effectiveness, kind of like expired cold medicine or vitamins.
Generally the expiration date is printed on the bottom or back of the package. If there is no expiration date printed on the package, the product is good for three years from the date of manufacture. Sanitizers that have added scents or colors may expire sooner and should have a date printed.