I don't wash the muslin all in one length, Hon.
I usually cut it in 3 to 5 yard lengths. It is too hard for me to try to handle (at my age, they try to tell me I am old, you know. ha ha) It also is easier to iron if you will remove it just ever so slightly damp from the dryer.
If I am not going to use it for awhile, I do not iron it at all! I wait until the moment of use! (Just dry it all the way if you are going to fold it away, as you already know!)
You are most welcome!!!
R