If the precut is a deep color (red, navy, black and some browns) I will hand wash in cold water with dish liquid (usually Palmolive - if I can wash a dog with it, I figure I can wash a FQ!), wring out and iron dry. Never had a problem with excess raveling. Have not tried to wash jelly rolls but have washed scraps (charm size and less) that I received from others by the above method without problems.
If the fabric is not prone to running (i.e., color), I just spritz with water, iron out the wrinkles and quilt away. I am not a prewasher, nor a quilt washer. (Uh oh...is that the quilt police I hear pulling into my driveway?
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