Not words you’d normally think of that belong in the same sentence, eh?
I forgot to consider colors running in the context of silk. I thought that was predominantly a rayon problem (and the store has some very very nice rayons as well.), but research I’m doing tells me that silks can run, as well.
I used vinegar to set tie-dyes. Granted, that was on cotton, but so what?
I’ve also been reading about using vinegar or salt to set the color. If it’ll help with silk, why not? Plus I also read that with silk, the first rinse should have vinegar in it to dissolve any remaining soap or detergent and to ensure the sheen is restored / maintained.
The easiest way I know of to set color with fabrics is to soak the article of clothing in water that has vinegar in it. Say, a cup of vinegar to a gallon, or something like that. Also, I believe cold water helps and hot water should be avoided (same thing with colored hair – hot water makes the color fade quicker).