I just rinse my Lambs wool mitt out with water, using the hose to blast remaining suds off, then fill it up with water and squeeze it until the water inside comes out through the seams taking any dirt or remaining suds with it, giving it a slight rub at the same time to aggitate any thing stuck to it.
Works quite well although the last stage may be for a bit of fun, to see how hard you can squeeze it before the water jumps out of the top where you put your hand in
If really soiled which is'nt very often may use a bit of detergent, always left to dry naturally after ringing it out by hand.
Chris