Follow these basic washing instructions for hand dyed silks, painted silks, and felted pieces for a lifetime of wearing: 

Use a dish tub or sink large enough so your item moves freely, or at least is not packed in. Fill with cool water and add about 1/2 tsp of gentle soap. (I use the Ecos brand, but anything labeled gentle, or green, or even baby shampoo will work well) 

Place your item into the tub or sink and gently press down a few times. Avoid agitating or wringing. Brighter colors, especially blues, turquoise and red will leave some dye in the water, but your item won't fade as the dyes are set. 

Gently squeeze the water out of your piece and refill the tub with fresh cool water, and add a splash of white vinegar. Repeat the pressing motion, add a little more vinegar if there is still color in the water. Remove the item and gently squeeze excess water out. Roll in a towel and hang to dry in shade or dry flat. Iron while still damp on the silk setting for best results. 

It's ok to dry clean your piece too.