I prewash everything in my laundry room sink. I clip the corners of the fabric, to minimize fraying.
I use hot water, and if I see that the fabric is bleeding, I add Retayne to the water. I then drain the sink and refill it to make sure there is no further bleeding.
Then into the dryer set on normal. Once dry, I iron it and fold it on a fabric board and store it on my stash bookshelves.