Clue box

Clue Box is a members-only item on the OSRS Grand Exchange in the other category.

In-game examine text: "Protects your clue scroll if you die."

It has a Grand Exchange buy limit of 50 every four hours, a high alchemy value of 6 gp, and item ID 12789.

View on OSRS Wiki

Clue Box shows an active flip setup with a margin of +27.8k gp and 654 trades over the last 24 hours.

At the buy limit of 50 every four hours, max profit per cycle is about 1.39m gp — high margin with healthy liquidity.