Hi Linda I clean mine every 3rd or so mowing using a low-teck stiff blade putty knife. I'm able to get most of the stuck-on grass off the underside of the deck. If you wait too long to do this, the residual grass seems to grow on the metal, making it very difficult to remove. I'd guess you can't tilt your riding mower over on its side, but you can certainly prop it up with blocks to do this.