Regular dusting is the best treatment for any lampshade. Using a soft cloth, brush, or feather duster, dust inside and out; vacuum a pleated cloth shade. Avoid touching the shade with your hands; oils from your skin can discolor the covering and attract dirt.
To clean a plastic or fiberglass shade more thoroughly, dust it, then wipe it with a cloth dipped in warm, sudsy water. Rinse and dry it. Avoid wetting glued parts or wires.
Rub spots from paper shades with a clean art-gum eraser or the absorbent material made for cleaning wallpaper. To keep parchment paper from drying out, rub it once a year with neat’s-foot (leather) oil or castor oil.
Cotton, linen, or silk shades should be professionally dry-cleaned because wetting these fabrics may cause them to shrink and warp the frame.
Some rayon and nylon shades that are sewn, not glued, to their frames, and have colorfast trims, can be washed. Check the label or hang tag. For best results, wash a shade on a clear, dry day when it can dry quickly so that the frame won’t rust.
First dust the shade thoroughly. Fill a tub with enough warm water to cover the shade; add a mild detergent. Immerse the shade and swish it up and down. If the water gets very dirty, change it and wash the shade again. Finally, rinse the shade in two or more changes of clear water. Blot it with a towel, then hang it over a bathtub or outdoors in the shade to dry. (Indoors a fan helps to circulate air and speed drying.) Sags in the fabric will disappear as the shade dries.
Don’t try to protect a new shade by leaving it in cellophane wrap. The cellophane may shrink from the lightbulb heat, warp the frame, and leave brown marks on the fabric.