They can be washed. You can use dish soap and warm water. Saturate then roll up. After an hour or so, unroll and brush with a soft brush as needed, rinse and let dry . I always treat with Aerospace 303 after a major wash.
2015 Freedom Express 248RBS
TV 2015 Silverado HD2500 Duramax
TST Tire Monitors
Honda 2000I + Companion
2 65W solar panels