We suggest mixing a detergent such as Dawn dish soap with some water. If your tubes aren’t heavily soiled, you can wipe them down with a rag but if they’ve gotten dirtier, you may want to use a scrub brush. We’ve found that one made for washing cars works well. Cleaning them while inflated has been far easier for us, but your mileage may vary
Give them a rinse with some clean water and let them dry before folding and storing.