I have been dyeing silk and silk/rayon scarves recently, and wanted to share some of my results. The first is a Habotai scarf I soaked in Citric Acid, scrunched the scarf on a piece of plexiglass, then applied colors with an eyedropper; I sprinkled rock salt over the scarf, let set for about 1/2 hour, then placed the scarf in a small plastic container, loosely covered with the lid, and nuked for 2 minutes, stopping at 30 second intervals to prevent overheating:
I really love the markings I got using this method, and sold a lot of them!
The next two are silk/rayon Devore cutout scarves I get every year from Dharma Trading. Because of the two fibers, I have had mixed results in the past. If I used a vinegar presoak, the silk would take the color well, but not the rayon. Using soda ash solution got the opposite results. This year, I decided to do two dyebaths, and have switched to citric acid instead of vinegar to eliminate the smell of the vinegar. Here are two that I did using various colors:

I really like how these came out, and again, I had great sales with these scarves!
Moral of the story: it pays to experiment!