Simple Green, diluted, and a soft bristle brush. No pressure sprayer EVER. Take both wheels off and while you're at it you might as well go ahead and wash the whole bike. Rinse the whole bike off first (I usually avoid the handlebars/tape), put the Simple Green solution in a spray bottle, spray the bike down, and scrub gently with the soft-bristled brush. Wash the wheels separately (it's just easier IMHO), use undiluted Simple Green on the cassette, chainrings, and chain - it's a great degreaser. Dry everything off with a soft cotton bath towel that my wife says isn't fit to use in the house any longer. Done!