A bucket with a plunger with a D handle sticking through the lid would surely do the trick.
Or dependant on if it's safe to do so, go for a swim in your clothes when available and pommie wash with scented baby wipes.
The best one I ever saw a mate do was wear the same clothes for almost a week then when in town buy new clothes and through the others away.
Mind you he is a dirty pom.
I am suprised no one has devised a PTO driven washing machine.
