I wash all my fabrics once they arrive to my home. I wash even the fat quarters or fat eights.
Of course, the fabrics fray.
I have a few pieces I bought from a shop in Romania (yes, I can find a few Michael Miller fabrics in Romania - www.fabrix.ro, how cool to order and have the fabric in 3 days!). They are cut from the bolt with a pinking blade. And today I noticed that they don't fray after washing, compared to the fabrics cut with a regular blade.
It must be more difficult (takes more time) to cut with a pinking blade?
I would love to have all my fabrics cut in this way. And the fat quarters too!
A few pieces from an older collection - Breeze by Rosemarie Lavin for Windham Fabrics.
I will sew new bags someday.
I do have a pinking blade. I use it from time to time.
Since probably the shops don't do the job for us, I think it is not big deal to "treat" the edges of the fabric with the pinking blade, before washing. The pieces will be a little smaller, but without this, after washing, with all that fraying, they have to be cut and become smaller anyway.
I will try this next time!