I just steam the charm packs. But I pre wash all fabric except if it is for chenilling.
It will all come to you a little at a time.
Some will say they never wash. If it is not the same fabric line they will all shrink at a different rate. You spen hours making a quilt and then you wash it and opps. Or you have colord that bkeed after you pieced the quilt...Opps again. I would rather pre wash and know it is colorfast and has shrank and my quilt will not surprise me later. I do also pre shrink my batting if I prefer not to have the crinkled look, but most of the time I like that look. Makes the quilt look like it is old....