Tibetan Butter Lamps are a conspicuous feature in Tibetan Buddhist Temples and monasteries throughout the Himalayas. The Butter Lamps traditionally burnt clarified Yak Butter but now vegetable oil is often used. Many people at home nowadays in the West use 'Tea Lights'.
The Butter Lamps help to focus ones mind and help with meditation.
According to the 'Root Tantra of Chakrasamvara' " If you wish for sublime realisation, offer hundreds of lights".
Pilgrims also supply the lamp oil to obtain 'merit'. The monks in the Temples and Monasteries manage the Butter Lamps and take extreme care to avoid starting devastating fires which have damaged many Temples and Monasteries over the years. Many Temples and Monasteries have separate 'Butter Lamp Houses' to house the lights.
Externally the lights are seen to banish darkness but they are also a 'search for enlightenment'.
Kalu Rinpoche said that offerings are of three kinds in four levels. Material ones such as Butter Lamps, imaginary ones that proceed from our minds, and things which are primordially extant. Light is certainly one of the latter, butter one of the first. When you think that along with the flame you are offering your consciousness and, or your energy, then the lamp stands for all three.