Frustration in trying to fix window

The damn kids broke my bedroom window and not the place is full of flies. Of course they got to do it on Sunday when there is no place to buy glass. I went over by the neighbor who collects almost everything to see if he had some glass. He only had some old aluminum windows without glass that he was saving to sell when the aluminum price is up. Anyhow, he told me that all I need to do is unroll a glass jar and use that in the window. I have tried three jars so far. One is a pickle jar, one is a jelly jar, the the other is a glass beer bottle (which is brown, so probably not good to use). Can someone tell me how the hell to unroll a jar. I dont have a clue how.