For donuts, a master log must be kept on EA servers of how many you have achieved/bought.When you cheat the value it'll revert back to this master value when you log back in (or return from visiting other Springfield).
You can get round this by doing the following..
After cheating up your donuts and BEFORE you leave the game, keep purchasing homer buddhas until you get some donuts. This may take a while and if you run low on donuts to buy them, simply change the value in game guardian back up.Once you find some donuts in the buddha/mystery box, you can safely exit the game as those donuts will count on the master log file.
Next time you in you will have those donuts, giving you ample amount to redo cheating if necessary.
Remember to do this every time you cheat the donut value.
