I love using my Frixon marking pen. I use Best Press spray starch and the marks are not visible afterwards. As for temp changes, it has been said a quilter mailed a quilt to a quilt show and it arrived with the marks showing, presumably after being exposed to an uncontrolled climate. So far, my quilts will not go to a show but I will mention to the recipient the caveat in regards to the markings. So, I would recommend them with a caveat of the temp sensitivity.