Excessive dampness may warp or discolor the slats, even if the wood is sealed. Dust can be easily brushed off with a soft dust cloth or vacuum cleaner attachment. This should be done regularly so that dust doesn't stick from the moisure in the air. For a deeper cleaning, remove them and lay them on a towel on a linoleum floor or outside on your porch.Clean and scrub with a soft nylon brush dipped in mild soap and water. Regular cleaning will keep them looking new or bring back some of the newness.