The World Health Organization has Five Moments for washing hands: 1  before patient care. 2  after environmental contact. 3  after exposure to blood/body fluids. 4  before an aseptic task, and. 5  after patient care.
This means that you can use leftover sunscreen from one year to the next. Some sunscreens include an expiration date â a date indicating when they're no longer effective. Discard sunscreen that is past its expiration date. If you buy sunscreen that doesn't have an expiration date, write the date of purchase on the bottle and be sure to throw it out within three years. Also, discard sunscreen that has any obvious changes in color or consistency.
Apr 08, 2008, 9:58 AM. I've heard it does diminish in effectiveness, but more importantly I came home with a nasty rash last year, and the doctor asked me if I may have used some expired sunblock, and I said yes, and he said that stuff can tend to break down after the expiration date and cause irritation.