Please use a mild soap made for fiber washing like Unicorn's Power Scour or Beyond Clean . Another option is "Soak." Do not use laundry detergents - they harm protein fibers!
Make a "bath" for your Paca Pressing Mat using about a teaspoon of liquid soap and 1-1 1/2 gallon of water. Gently submerge and don't agitate. I let mine sit about 5 minutes. Rinse twice same temperature water.
After rinsing, allow the mat to rest and drain on top of the bucket or container while still in the sink. Then place flat inside dry towel (on floor) and step on it. This will wick out a lot of the water, Finally, rest on top of folding rack flat or on cookie cooling rack. This will allow air to circulate and the mat will dry more efficiently.