I wash everything. Batiks bleed and cotton fabric shrinks. I have found that my fabric has been shrinking a lot WOF this is how the jellly rolls are cut, so I always wash mine. Just fill your sink with warm, almost hot, water, add a few drops of liquid washing machine detergent and swish them around for a while. I rinse well with cool water, then spin them in a salad spinner, about 10 strips at a time. Then I let them air dry till almost dry and iron. If I'm going to cut them into triangles, I'll hit them with spray starch. As one poster said, they shrink like crazy. I wonder how a quilt would look with all the shrinkage only going in one direction? As far as the batiks are concerned, you want to at least test to make sure they don't bleed.

I don't pre-wash anything unless there's white in the quilt.
It's easier to work with unwashed fabric.
Been quilting since the 70s - back then I did wash everything - got lazy and found it made no difference.

I've been sewing since the 1950's - I still think it's worth the effort to wash everything washable before cutting it.

Guess we'll all have to agree that what we do is what works for us!

I don't prewash anything. When the quilt is done, I wash it in warm/cool water and use vinegar in the rinse water to set the colours. Never had any problems, but everyone should do what feels best for them.

Batiks definatly bleed...... Depends on the color for how much bleeding. I had some yellow/orange and it didn't bleed nearly as much as some red/purple.
If its all batik fabrics I'd say color catcher several times in cool/warm water and then heat up the water depending on how much bleeding is going on. Good luck.