It is not necessary to "wash" fabric, as in adding detergent or soap. Plain water will dissolve the noxious and potentially dangerous formaldehyde (remember what you learning in Biology 101 when dissecting? It is a preservative with bad possibilites). One should definitely "RINSE" fabrics, when making a quilt for BABY. I've researched and written a lot about this topic of quilt care. Personally, to shrink fabric, I sometimes just spritz it and iron it before using. Seems to work.