Problem with Slot GUI, but with Input slots.

So I saw that some people were having output problems, and I saw that the solution was to use block events instead of GUI events. Block events don't provide an inventory, so I ditched the output slot and made the item spawn over the block. When you press a button, certain items are consumed and the item spawns on top. If I close the GUI and open it again, the input items reappear. How do I solve this?