Yes, you can put potholders in a washing machine but only with other potholders and other utilitarian fabrics like towels. However, deep cleaning of potholders requires more than a machine wash. You can try putting all your potholders in warm water with soap for 10-15 minutes, then launder it as usual. If this doesn’t work and your potholders are full of stains, you can directly boil them with soap for 30 minutes. Try removing the stains with a brush, and then, wash them. The last process doesn’t require a machine wash after boiling. If you keep washing your utility fabrics weekly, we don’t think you have to do such hard work to let go of stains, oil, and grease.