Wheel Cleaning During Water Restrictions

My question is: how do you (or would you) wash wheels and/or tires if you`re restricted in how much water you can use? This is probably a method and tool question.

What I`m doing now, is if I`m going to use one bucket, I`ll mix a 3 gallon mixture (instead of 2), and when done with the body work, I`ll do the wheels and tires with a Megs wheel brush and an "el cheapo" spoke brush. I do have problems getting the wheel barrels clean from brake dust and I`m trying to avoid dropping coin on a $25 + shipping brush.

Anyway, how and what to you use to get your wheels/tires clean when H2O is an issue?