Clay

Clay is a free-to-play item on the OSRS Grand Exchange in the ores category.

In-game examine text: "Some hard dry clay."

It has a Grand Exchange buy limit of 13,000 every four hours, a high alchemy value of 1 gp, and item ID 434.

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Clay shows an active flip setup with a margin of +3 gp and 80,084 trades over the last 24 hours.

At the buy limit of 13,000 every four hours, max profit per cycle is about 39.0k gp — high margin with healthy liquidity.