Personal hygeine is a topic that doesn't seem to get a lot of print when it comes to Mars settlement, but is something that will have to be dealt with in the course of things.

For NASA, the immediate problem is how to stay clean in zero-g, aboard the Shuttle or the ISS. And of course, they've gone and done some research on the topic. It's a fascinating paper, covering the various methods that have been tried in the past (note the sauna aboard Mir -- what a great idea!) and some that may prove useful in the future.

All things considered, though, this is one more reason why it's better to settle a planet than to colonize an orbit.