I bought 2 1/2" strips from Keepsake Quilting. Should I prewash these before sewing them onto a sweatshirt that will soon be a jacket. I will be totally covering the sweatshirt with fabric.
The strips are all shades of blue batiks from very dark to very light.

is the sweatshirt 100% cotton? I don't pre-wash most things, would never pre=wash a strip for fear of losing most of it to strings and distortion. But I would sew the unwashed strips onto the unwashed shirt and let them shrink together. That's what I did on a sweatshirt I made into a jacket.

I already washed the 100% cotton sweatshirt. Oops!

You sound like me.

Sibyl

I guess I'm more concerned about the colors bleeding than shrinkage. Should I be worried about shrinkage? I think I will just give her a couple of color catchers when I give my mil the jacket.

I wouldn't. They will probably fray.

I wouldn't wash them..too much fraying. I made a similar jacket using various shades of blue batiks and I can't stop looking at it because the colors are so pretty. Your MIL will love hers!

I never wash pre-cuts. It makes a mess.

I agree with the others...too much fraying...

I wouldn't try to wash them, could end up a tangles mess and hard to sew