Then, click the right side of the valve to the right twice, so the tar should be flowing at maximum. You should see the 'pressure' indicator on the left go up. When the indicator reaches the green region, click the right side of the valve on the left once to let out pressure. This should stall the indicator on the left. Now you can start to add more coal. If it's above, don't add coal until it drops. The bar on the bottom will start turning green. When it's full, you can stop adding coal and close the window on the top right to get your barrel of naphtha.
Unsurprisingly, a Barrel of naphtha is tied for the heaviest item in RuneScape, along with Stone Slab and Big rock weighing at 32 kg, and letting a player hold 896 kg of weight, with a full inventory.
|Item quantity required||1|
|Base junk chance||98.9%|
|Part 6 of the Elf quest series|