All energy emits light on a spiritual level. Positive/pure energy is the brightest, which is why many spells ask that you visualize "white light".
We can store energy in any object.
Some witches tie knots and store energy in the knot, later to untie it and release the energy. Some do the same with bottles, lockets, poison rings, etc. I personally use a poison ring to store ashes of a spell I wish to carry with me. No I don't put poison in it lol, but they are neat little compartments to store drops of oil, powders, ashes, and the like! Just becareful not to eat with them on if they can come loose easily, ick!
But going back to objects, candle magick is a perfect example as to how witches empower objects. The candle is charged and programmed for a particular purpose, then burned to slowly let off the energy put into it. Some witches like to sit and continue to focus more energy into the spell, so energy is being released from two sources (them and the candle) instead of just one.
Talisman, charms, and amulets also store power that we put into them. These can be just about anything-- an iron nail, gemstone, rock, jewelry, paper, plant material, cloth, you name it! Usually ones to release power or a spell are items that can break, open, dissolve, or destroy. This is why we burn paper in wish spells.
Edible charms are used to absorb the magick into the body, released upon consumption, commonly used for healing purposes. But you would need to read into kitchen witchcraft to do that.