1) Thoroughly wash the footwear with a solution of 1 part mild phosphate free soap, to 4 parts water. Work this solution into the footwear by soaking, and gently massaging, the solution into all parts of the slippers.
2) Very thoroughly rinse the footwear. The easiest way is to run the footwear under cold - lukewarm water, massaging the water into the footwear, until it runs out of the footwear clear.
3) Pat dry the slippers as much as possible. Do not wring them, or place them in a drying machine, as this can stress the construction of the footwear and permanently damage it.
4) Place the footwear in a warm, dry, area and allow them to fully dry at least 24 hours (or until all moisture has evaporated.)