If you can't, I would have to undo a whole bunch of quilts. Depends on how picky you are. If you are very worried about uneven shrinkage or color bleeding, it might not be a good idea. I have a long list of other things to worry about so I choose not to worry about any of that. Batiks, reds and blacks have a reputation as more likely to bleed and cheaper quality fabric tends to shrink more.