In the Item menu, the trash can exists at the bottom of the inventory to discard unwanted items. However, the player can use the trash can as an item at certain times, and for a certain amount of uses, depending on how many total MAGI the player has in their possession.
Depending on the MAGI total and what MAGI the player has equipped, they can "use" the trash can item on the party. The best time to do this is after getting the Pegasus MAGI in the Nasty Dungeon. Having 68 MAGI causes the trash can to dole out Speed potions to humans and mutants, giving them three Agl per use. Depending on what MAGI the player has equipped, they could use the trash can up to 72 times. One MAGI-equipping scheme that allows this is by equipping Prism, Speed, Aegis, and Power MAGI, respectively, on the four units.
If the player uses up all available uses of the trash can, the MAGI total changes to 255, but will be shown as 99 on the screen. The player can use the trash can much earlier in the game for other effects, but changing the MAGI total to 99 early in the game could cause one to get locked out of certain worlds since the doors found on Celestial World looks at the player's MAGI total to see if they can unlock them or not, and if the player messes with their MAGI total, their game could become unplayable. If the player does use this early, to not get locked out they will need to go forward to Valhalla World and visit Valhalla Palace, then backtrack to Nasty Dungeon and grab the Pegasus MAGI. This makes the MAGI total 0, but ensures the player can use the Pegasus MAGI at any time to warp to where they need to go.