There was an file or something. You'd delete the game, all traces of it from your phone, logout of game center, then redownload it, then put the file you got into a program called iFunbox (I think). It would connect to your phone, and you could just load the app on your phone and you'd end up with all the money and stars you would ever need. I haven't played in years, so I don't remember too well exactly how it's done.
Ah okay. Thank you for that! I'm going to redownload the App just to test this for fun haha.