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.
Does Sodium Chloride expire? I got a 2nd degree burn about 4 months ago and a week after wards the clinic gave me NaCl to clean it after it dried. Looking at it now, It says it expired in 2009!!! And, I'm wondering, does this stuff really expire?