Don't bleach white fabric whatever you do because it will turn yellow...and eventually it might disintegrate and fall apart...I had yellow bleach marks on one of my white tablecloths once after I bleached out some stains...is it possible to remove the piece and sew in a new one...or sew a piece of white fabric to the back of the white where the sticky stuff is...even if you baste it in..it will become permanent after you quilt it???