I have area rugs throughout my house.  This is the only mat that nails the rugs to the floor, making them easier to clean.  When one walks on carpeted floor, sand and dirt goes through rugs and is stored in the mat below. So no matter how often one has carpets cleaned or in my case, I send the orientals out for washing, the mat is still dirty.  I pick these up and wash them.  Either allow them to air dry or dry under the air cycle of dryer.  Works great.