There is more than one way to clean these shoes. Most people might think that the good old washing machine is the only way to get them clean. They would be wrong. If the shoes are white an old rag with some bleach will do the trick very well.
In a hurry, a Mr.Clean Magic Eraser will work fairly well. Then there is always the very versatile baby wipe. At some time or another, I have used all of them.
These shoe-cleaning tricks work on plastic clogs as well. It’s an adventure to find just what cleaning things will work on other items besides what they were originally intended for. The classic example is the lemon slice and salt to clean copper bottom pans. Who would have thought?