I no longer use the washing machine to prewash. I soak the fabric in hot water in the sink and then put it into the dryer to pre shrink.

Thank you everyone for your varied methods will try them. I'm fed up of the tangled mess. I have been not washing for the last 4 months due to an operation and I have been frustrated at no wash. Again thanks

I only prewash questionable fabric, reds, batiks, and unknowns....I use my wavy rotary blade and get next to no ravels, I also do use the delicate cycle.....and only hot water if I really question the fabric.....always dryer....if the fabric is either muslin or flannel I have been know to do this twice, but never if for a rag quilt that will be made with
all flannel....

I have a friend who made a beautiful appliqué vase full of flowers, a work of love as she is partially sighted. After finishing she decided to was as sh like the shrink look on her quilts etc. one green ran slightly. She is thinking of washing first. This is very difficult when you go to a class in a quilt shop and purchase from there to use immediately.