Mylar is one of the best reflective materials but can be difficult to hang without getting hand prints or wrinkles. The best thing to do is to buy a 2 mil Mylar, it does not wrinkle as easily. Put socks on your hands to stop the finger prints from ruining the reflective capability of the Mylar. Mylar is not washable so you want to keep it as clean as possible or you’ll need to replace it. 2 sided tape works great for attaching Mylar to the needed surface for most applications.