I agree with all the above(except windex). Low heat is most important. I have a box of insulin syringes from way back. Don't know why I have them, but they come in handy for bubbles in covering. The needles are so small that I can go over any area with bubbles and peck at the bubble(s) like a miniature woodpecker and then touch the bubble(s) with the covering iron. Gas bubble(s) disappears and the the little holes can hardly be seen. Insulin syringes are cheap and can be bought at any drug store.