Take a Tic-Tac dispenser from your pocket. As it’s transparent, it’s obvious to all that there’s just one piece of candy inside. This is no illusion, there really is just one dispenser with one piece of candy inside.
Open the dispenser and dump the Tic-Tac into your spectator’s hand. The dispenser is now empty and you show it from all sides. The spectator can look inside the opening and can see that it’s just an empty Tic-Tac dispenser and nothing more.
Close the dispenser and hold it horizontally between your thumb and forefinger in front of the spectator.