What ever they are going to do I want them to do before I put them in a quilt. I wash precuts by hand but fat quarters and larger go into my washer. I don't want any surprises when I wash my finished quilt for the first time.

Thanks to all for your answers.... I will prewash!

I hate to say it - but I do not like the JoAnn batik fat quarters - I think they are of a coarser fabric. I do not know about their batik fabric on the bolts though - have not bought any of it. Yes, I always prewash (handwash) all of my batiks -including fat quarters. I use my pure white dish pan - put in a little warm water with a drop or two or liquid dish soap (Dawn) or Tide - swish the still folded fat quarter in the water and see if it bleeds. If not, then I rinse in cool water and wring dry gently - then roll in thick towels - then hang them up on an inside clothesline. Very little wrinkling. I do iron when I use the fabric later.

I agree -- I don't want any surprises so I wash before I use the fabric -- especially batik and flannel. I didn't used to and paid the price.

I have to say that even with batiks I don't prewash unless it fails the "white paper" test--my friends that own a quilt shop say that with quality fabric, you rub a piece of white paper very hard on the fabric--if you get ANY dye, you need to wash, otherwise you a good to go(unless of course you have a sensitivity or allergy to fabric chemicals)

I personally don't use batiks, but the bleeding would make me want to prewash if nothing else. I personally prewash everything, even pre-cuts, they can be put in water and dried over towels.