I wouldn't worry about it to much. Some batts say to wash before using. I have never done that. I can't imagine what would happen to a batt if I put it in the washing machine. I certainly am not going to wash something like that by hand unless it is for a doll quilt size piece. If the quilt is meant to hang on the wall it will probably never be washed anyway. If it does shrink horribly it wasn't good fabric to begin with.
Good luck.