I soak my playsilks in vinegar first, it helps to even out the dyeing. I have a bunch I made with kool-aid for my dd, and they are still vibrant, orange, purple and red.
Some people use koolaid and other drink mixes, some professional dyes, and some natural dyes.
I use special craft inks(regular ones bleed) too to stamp words and images on them.
I first found out about playsilks when I was homeschooling my ds and visited a waldorf winter solstice event. Most in the waldorf community use muted, natural dyes, and some use cotton gauze for a sheer look(cotton would also be vegan, where silk comes from the silkworm).
So I first saw them on wooden playstands as a canopy. then I learned all about them. Dress up: scraves, hats, capes, dresses, wings, for your nature table they become landscapes, rivers, meadows, oceans, dolly blankets, dolly slings. I've used them as natural gift wrap on occassion, especially to my own dd, lol They also make great fashion for us adults! There are some that are more see-thru than others, great for infant/toddler peek-a-boo.