Some manufacturers provide cleaning instructions for their camp chairs, so always check to see if any were included with yours. To clean a camping chair made of polyester or another canvas material, start by brushing off any dirt with a soft bristle brush. Then, mix 1/3 warm water and 2/3 vinegar in a spray bottle, and scrub the fabric after wetting. Use a mild soap to wash the chair legs. Set the chair out in direct sunlight to dry.