The windex forms a very thin film and holds the covering down very flat. Then the windex will evaporate out. Most brands of "windex" type window cleaners int he US have amonia in them and this can activatre the adhesives in some film coverings and make them stick. You can also use soapy water to stick them down temporarilly.

For best results you can then go back over just the edges AFTER all of your windex or other liquid has evaporated and dried with a low temp iron to seal the covering down. Or you can take a cotton swap dipped in acetone and run it along the very edge of the covering to "activate" the adhesive. The acetone works with monokote but not orocover/ultracote.

Do a search on windex and you will find some really good threads that discuss the technique in depth. Termagator does incredible stuff with this technique. Have tried it and have gotton really good results. Way better than trying to iron down overlays.

Eric