We don't recommend the washing machine as it may fade the signature and print number on the back of the deskpad. The best method is with dish soap/hand soap, water, towel and a sponge. Apply a small amount of the soap. Then add some water to your sponge and gently scrub in the soap into the deskpad. Make sure you're gentle with this process. Once you have thoroughly scrubbed the impacted area you want to dry off the remaining soap and water with your towel.