"TO FIX: Use a 225° iron with a pieceof plastic oven cooking bag or parchmentpaper as an ironing shield. If you irondirectly on Poly-Spray, it melts thevinyl and gets silver on the iron.Worse, it leaves iron track marks in thePoly-Spray. Messy. Better yet, get a thinpiece of sheet Teflon from a local plasticssupply store to use as an ironing shield.That keeps the Poly-Spray pretty much"

The info above is from the Polyfiber manual.
I used parchment for smoothing down the pinked edges of tapes and any little hiccup with PolySpray. It worked great.