Go to the junk yard and find a vehicle with an intact door window. Ask the man who owns the dog whether he would mind you destroying that window. If he minds ask how much it would cost or what the cheapest one would cost. (Don't look for a window on a vintage MG but something on an old jeep would work.) Then use some duct-tape to cover the window (this will minimize the amount of glass shards you leave in the yard. Press the center-punch against the glass until you hear a pop. At this point you should notice that the entire window has shattered into little pebble sized pieces (which will rain down on your toes if you didn't do the duct-tape thing correctly) If you hear the pop but the window still doesn't cooperate then you are probably working with a liminated window - windshields (front and back) are laminated and some of the newer tinted side windows are laminated. This will work with tempered glass but not with laminated glass.