Huge smouldering lamp is an item obtainable via Treasure Hunter. It grants the same amount of experience as a huge prismatic lamp, but if a skill is chosen that has bonus experience, up to the same amount of bonus experience is converted into normal experience as well.
If used on a F2P world, the lamp will give a warning that only rubbing it on members worlds will use up the bonus experience. If the player uses the lamp regardless, it will not convert any bonus experience.