Buy RS3 Teak pyre logs
Teak pyre logs are teak logs treated with sacred oil. They are a members-only item in RuneScape 3. You need level 40 Firemaking to light them.
These logs are used in the Shades of Mort'ton minigame. Place them on a funeral pyre with a set of Loar, Phrin, or Riyl shade remains. Then light the pyre with a tinderbox. This frees the shade and gives you 120 Firemaking experience and 33.7 Prayer experience. You also get some coins or a key. The type of key depends on the shade remains you burn, not the logs.
Teak pyre logs can also cremate vyre corpses. You can do this in the Columbarium under Paterdomus temple during and after the Legacy of Seergaze quest.
Making these logs yourself takes work. You must buy olive oil, help rebuild the Mort'ton temple, and turn the oil into sacred oil at the altar. Each set of teak pyre logs needs three doses of sacred oil. Buying them ready to use skips all of that.
Teak pyre logs can also be disassembled. They give Simple parts most of the time and Living components on rare occasions.