Yes, the fabric needs to be prewashed, you could either just soak them in a sink of water or put them in a pillowcase when you wash them to keep the fraying at a minimum.
Originally Posted by zjsquiltymomma
I'm new to quilting after not doing it for so many years...I have a quick question...I have a jelly roll made up of 2 1/2 inch strips. I want to make my 2 1/2 in. squares out of them. Do these strips need to be washed before I cut them?