If using dyes that are steamed set. The dry silk is steamed to set the dye permanently into the silk. This makes the piece completely colorfast and washable. However, if silk is left in direct sunlight for long periods of time the silk fibers will be weakened and some colors may fade. Silk paintings and wall hangings should be given the same consideration any fine art piece would receive.
Silk is a organic protein fiber and will dissolve in chlorine. Therefore all silks should be washed in pure soap, preferably colorless soap. Clear dish washing soap or shampoo are fine.
With simple care your fine silks will last for many years.