This photo shows a grey mare cantering in front of a white barn in late fall. Recent rains have made this mostly white mare appear to be more of a dingy grey. The best way to clean a muddy white horse is to allow the mud to dry completely, then flake off the dried mud with a rubber curry comb. (some prefer a metal curry comb, but metal curry combs will damage the hair) then groom thoroughly. If the weather is warm enough, a bath (even without soap) is the easiest way to clean a white horse- just make sure you let the mud dry and chip it off before you bathe, otherwise efforts to hose away the dirt will take forever!