Care
There are far more interesting things to do in life than handwash your underwear. All the fabrics we use are colourfast and are chosen to need no special care whatsoever. Wash with your normal detergent in your normal 30 or 40 degree wash. If you want to stop them getting tangled up with your jeans, perhaps pop them in a little net bag or a pillowcase with an elastic band round the end. But they'll be absolutely fine without.
We recommend drying them in the air rather than the tumble dryer and, just in case anyone needs to be told, no ironing.
Easy peasy!