Your window coverings should be cleaned regularly to avoid discoloration, dust buildup and mold. To help keep your drapery fresh you can shake them out daily to remove any dust. It is also a good idea to vacuum them monthly. Only do this if there are no loose pieces on the drapes. Also use the brush attachment on your vacuum for cleaning.
On a regular basis, you may also be able to clean them in a washing machine. Check the drapery cleaning instructions for the drapes to be sure that they are washable. Keep in mind that older drapes or those that have a lot of sun exposure may have weak fabric threads that could further deteriorate in the wash. If you don't feel comfortable washing them yourself, it may be better to have them professionally dry cleaned.