Never pre- wash a batting, it will shred in the agitation. You can pre- shrink a batting if you do not want that antique crinkly look . Poly battings never need to be preshrunk as there is no shrinkage in poly. Most manufactures list on the package the expected shrinkage, and guidelines for preshrinking if desired. They also indicate on the package recomendations for how far apart the it should be quilted.