I throw mine outside and hose it down, scrub it with a broom soap and vinegar and they are at least 20 years old and still going. when I don't needs the ruled lines, I turn the mat over and cut on the back, I just draw a straight line up and down and across, for when I need to line up. Oh if you are going to do this, make sure it's at sunset when no sun is in that spot lol....