Someone talk me through cleaning a mouse pad?

cloth ones are easy. warm water in the sink, a little dish soap, scrub the top with a soft brush or an old toothbrush in circles, rinse until the water runs clear. Press it between two towels to get most of the water out, then let it air dry flat for a full day. The bit that catches people out is the rubber base. Don't put it in the dryer or near a heater, the backing warps and it never sits flat again. Also don't soak one with stitched edges for ages, the stitching can lift. Hard plastic pads just need a wipe with a damp cloth.