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.
I have been using the Fraxel RE:restore for 5 years and have treated pigmentation of the face, neck, declotte, hands/arms, and shoulders with great success. If the patients follow our instructions regarding suntanning and use of UVA/UVB sunblock with an SPF of 30+, their results can last years.