Check the can. Many quilting sprays will only work with cotton batting and cotton fabric. I don't know that I would spray a customer quilt unless I checked with them first. If you do proceed with the spray, make sure that you use sheets or something to cover EVERTHING except the batting. The spray will go everywhere and if you get it on your rollers it will be a mess. Hope you told her that there was going to be an extra charge for this. I think it's going to be a whole lot of extra time fiddling with it.