If a player must put one or more cards from their Main Deck in any other zone, such as the Trash, in excess of the number of cards in their deck they will do so as much as possible, perform this action, and then complete the remaining number required by the instruction.
§ 431.1.b Core Rules PDF (officieel)
§ 431 Burn Out
§ 431.1 Burning Out is an action a player must perform if they attempt to move one or more cards from their Main Deck to any other zone in excess of the number of cards remaining in their Main Deck:
