Cleanse Tag is an item which was introduced in Generation II. It is held by the first Pokémon in the player's party. The effect of this item is to let wild Pokémon of a level lower than the holder not to appear.
Omega Ruby and Alpha Sapphire: It can be found in Mt. Pyre.
The Japanese name of the Cleanse Tag, "Ofuda" (御札 or お札) is a type of household charm, amulet or talisman issued by the Shinto shrine. It is hung in various houses for protection.