I have some washable rugs - two of them are sort of rag rugs (same rugs, they were cheapo, each something like 6 x 9.) I used to keep one under my easel.. My washing machine will take one of them, and when I washed both at the same time, I brought them to a laundramat for one of those big washers. And, truth be told, I've run some of the bigger rugs on a cable clothes line and hosed them down, after vacuuming. Not my best rug, though.
Anyone remember rya rugs? That's another one I wish I still had. Well, had two of those too.