http://viewonbuddhism.org/general_symbols_buddhism.htmlThe Eight Offerings:Offering water to cleanse the mouth or face: It signifies auspiciousness or all the positive causes and conditions which bring positive effects. So, make an
offering of water which is clean, fresh, cool, smooth, light, delicious, comfortable to the throat and stomach - these qualities are the qualities of auspiciousness.
Offering water to wash the feet: This is clear water mixed with incense or sandalwood which is made as an
offering to all enlightened beings' feet. The symbolic meaning is purification. By cleansing the feet of the enlightened beings, we cleanse all our own negative karma and obscurations. By making offerings to clean the enlightened beings feet, we are really cleaning the "feet" of our own mind.
Offering incense symbolises moral ethics or discipline.
Offering light signifies the stability and clarity of patience, the beauty which dispels all ignorance.
According to Ven. Norlha Rinpoche: "It is also excellent to offer the butterlamps, candles or light because this act of offering this light symbolizes burning away our mental afflictions of desire, aggression, greed, jealousy, pride and so forth. The other part of the symbolism is that it is a way to burn away our illness."
"Offering butter lamps is the most powerful offering because their light symbolizes wisdom. Just as a lamp dispels darkness, offering light from a butter lamp represents removing the darkness of ignorance in order to attain Buddha’s luminous clear wisdom. The lamp offering is a sense offering to the Buddha’s eyes. Because Buddha’s eyes are wisdom eyes, they do not have the extremes of clarity or non-clarity. Our ordinary eyes, however, are obscured by the darkness of the two defilements –gross afflictive emotional defilements and subtle habitual defilements. While the Buddha does not have desire for offerings, we make offerings for the purpose of our own accumulation of merit & wisdom. Through the power of this accumulation, we can remove the cataracts of our ignorance eyes in order to gain Buddha’s supreme luminous wisdom eyes. When we offer light, the results are the realization of Clear Light wisdom phenomena in this life; the clarification of dualistic mind and the dispersal of confusion and realization of Clear Light in the bardo; and the increase of wisdom in each lifetime until one has reached enlightenment.
Traditionally, butter lamps are also offered as a dedication to the dead in order to guide them through the bardo by wisdom light. We can pray as well that this light guide all beings of the six realms, removing their obscurations so that they may awaken to their true wisdom nature.
With genuine faith & devotion, visualize that with your offerings, countless offering goddesses offer immeasurable light to all enlightened beings. You may recite the ‘Butter Lamp Offering Prayer’ from the Collection of Offering Prayers.” Lama Tharchin Rinpoche
Offering of perfume or the fragrance from saffron or sandalwood. It signifies perseverance or joyous effort. Through that one quality, one develops all the qualities of enlightenment.
Offering of food which has a lot of different tastes signifies samadhi, which is a nectar or ambrosia to feed the mind.
Offering of musical instruments. There are different types of instruments -- cymbals, bells, guitars, lutes - - all of these are offered. Their nature is wisdom, which makes an
offering to the ears of the Buddhas and Bodhisattvas and all the enlightened beings. Sound represents wisdom because wisdom is a special power of the mind which penetrates phenomena. Compassion is achieved through great wisdom; interdependence of all phenomena is realised through great wisdom. of course all phenomena have the nature of interdependence, causes and conditions, but sound is especially easy to understand.