Ideally, you should wash your mask after each use. When you return home after running errands, carefully remove your mask and either launder it by hand immediately (use very warm, soapy water and rinse thoroughly) or store it someplace where you’ll remember to toss it into the washing machine with the next batch of regular laundry.
I know that washing your mask every time you use it isn’t very convenient – and I can imagine you might be tempted to skip it – but it is an important step for avoiding the virus. Each time you wear one, it could come into contact with infectious material that could linger on the fabric, and then transfer to you, undoing all of the protective work the mask did for you in the first place. Washing your mask can destroy any lingering bacteria or viruses so that it’s safe to use again the next time you leave the house.
Most masks can be washed in a machine with your regular laundry. Use the warmest appropriate water setting for the clothes being washed. Then either dry your face mask in the dryer on a hot setting or allow it to air dry, preferably in the sun.
You should make or buy multiple masks so you always have a clean one ready to go. Stash masks in handy places – the car console, your purse, your briefcase – so you’re always prepared to protect yourself and others when you go out.