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.
A: Expiration dates are often stamped on sunscreen containers to specify the time limit for a productâs stability and efficacy. For optimal sun protection as well as texture, stability, and sterility, use the sunscreen prior to the date listed. If you canât find a date on a new tube or bottle, write the month and year you purchased it in permanent marker on the tube. To test shelf life, manufacturers store a product at 40Â°C with 75 percent humidity; then at 40Â°C with 25 percent humidity; and then test it at 0, 1, 2, and 3 months. Stability for three months in these laboratory conditions is comparable to three years in normal ambient environments.