[Perfectlap]

canvas and car wash soap are not friends. the detergents attract dust which breaks down the threads. If you get soap on the top rinse it out thoroughly.

one more on the No Rinse solution if you don't have regular access to a hose. You can get away with one bucket of warm water and two shots of the No Rinse. Use a sheepskin mitt or a chenille sponge. dunk the mitt and hold it over each panel to wet down the car. then simply wipe in the direction of the wind. dunk the mit before moving onto another panel. To dry off the car use a waffle weave towel. Probably a good idea to use a spray wax or quick detailer before wiping.
With the remaining water in the bucket use a wheel face brush(Meguiar's Gold Class for intance) and brush down the wheels.

I actually use No Rinse instead of doing a full bucket and hose wash. Cuts down on the paint swirling.