How do you get rid of key items in HeartGold?

In Pokémon HeartGold, key items cannot be dropped or sold like regular items. However, some key items can be given to certain NPCs to remove them from your inventory. Alternatively, you can deposit key items in the PC storage system in a Pokémon Center to free up space in your bag. It's important to note that some key items are necessary for game progression and cannot be discarded.