I’m an ultralighter and learned how do ‘astronaut’ shower/shampoos with <1L of water, Dr. Bronners, water bladders (Evernew or dirty Sawyer), and a spare Smartwater cap with holes drilled in -
CLICKY. It’s easy to practice at home.
Summer I take daily cold showers after setting up camp. In chiller weather there’s a number of options to mix and match as necessary:
- warm a little water with a stove, or fill-up off a public bathroom hot water faucet
- pitch my floorless pyramid tent in direct sunlight (zeros windchill and captures “greenhouse” warmth), and take a sit-down shower on the corner of my polycryo groundsheet.
- if really cold, I just do partial gravity showers: ie, shampoo while leaning head over/upside down; and then just waist down shower w/o pants - I can deal with the partial/temporary cold shock for those. Torso and arms just get sponge baths. Course, the need to bath in cold weather is less frequent.