|I am a firm believer in dry cleaner avoidance, so if it doesn't go in the washing machine I don't buy it. I have found over the years that most rayon will wash just fine IF you make allowances for shrinkage of yardage AND you test a strip first.
I tear off about a six inch strip crossgrain, pop it into a lingerie wash bag with a dye trapper sheet (Shout makes one) and put into the next washer load of similar color. It goes into the dryer as well (keep it in the bag for that trip as well). If it compares well to the original yardage for color and texture (or if I like the results), the whole thing goes into the wash by itself. The dye trapper sheet gives me a good idea of how much ink has been thrown off (I used to use a piece of muslin for that, but I feel this is more accurate). If it's too much, I could dry clean the stuff once I had finished the garment. There is so much shrinkage in rayon I don't feel comfortable not preshrinking in any case.
One odd thing I have found to be true is that you need to use detergent in the load. Without it, you won't get as much shrinkage NOW (but you will later).
When the garment is finished, I machine wash it but hang it to dry. When the garment is dry, I put it in the dryer for about fifteen minutes to heat out the wrinkles. This also works well for woolens and dress shirts, but it does set any remaining stains you may have missed.
Yes, I also wash silk, but that is very much on a case by case basis.