The infinite balls glitch, also known as the Poké Ball amount bug is a glitch in Pokémon Colosseum which allows the player to repeatedly use any type of Poké Ball (including the Master Ball) without decreasing its amount in the inventory.
A Poké Ball to be reused
Another kind of Poké Ball
At least two Pokémon which have not fainted in the player's team.
Enter a battle.
On the first Pokémon's turn, use the Poké Ball that will be kept.
On the second Pokémon's turn, switch the first Poké Ball's position in the Items menu.
While it will look like the first Poké Ball is being used, no Poké Balls will disappear from the inventory at all, and the game will still treat the situation as if the player had thrown a Master Ball (or whichever kind was selected) at the opponent.