The lamp oil used for fuel is obtained by distilling swamp tar in the chemist's in Rimmington or at the lamp stall in Dorgesh-Kaan. When filled with fuel it becomes a bullseye lantern. Level 49 Firemaking is required to light it. Bullseye lanterns can also be stolen from chests in Dorgesh-Kaan, which require either 52 or 78 thieving (either one yields them very often). They can also be stolen from cave goblins or purchased from Miltog in the Dorgesh-Kaan marketplace. Some of these methods will still require the use of lamp oil to complete them.