There are many ways to cleanse any unwanted energies in your aura. Some of these are physical acts like smudging or showering. Some are visualisations . When we speak of cleansing the aura, we are not implying that it is "dirty," but one can over time, especially when dealing with other people through the course of a day, pick up bits of their energy and emotions. These may be positive or negative, but they are not yours, and can effect your ability to stay grounded and centered in your truth.
A favourite technique is to burn some sacred herb or incense and let the smoke waft through your aura, carrying any impurities away. Sage is used commonly, both by Native healers and shamans and by witches. Some other herbs used in cleansing incenses are Hyssop, Cedar, Eucalyptus, Rosemary, and Lemon.
Water, of course, is purifying. It can be sprinkled into the aura or one could take a shower...with hot water or rain water! One may want to use saltwater or water with herbs infused in it, or water with essential oils in it. One may use a sprig of a herb with cleansing properties as an asperger to sprinkle the water upon oneself; favourite herbs for this are Hyssop and Rosemary. One can also visualise a shower...and make the water droplets golden, white, rainbows or any other colour that seems appropriate . Sitting in a bath, feeling negative energies seep out the pores also works; it's fun to imagine the dark energies swirling down the drain as the tub empties.
Of course, light can cleanse your aura, too. Letting white or gold light flow in through your crown, through your aura and body, and down your grounding cord will remove any unwanted energies.
It can be interesting and useful to spend some time imagining mists, smokes, rains, and lights of different colours filling your aura. How does a golden rain make you feel? What about a green mist? Or a purple smoke? Or a glowing red light? If you experiment in this way, note the colours that feel good for you, and go back to them for a while before you close.
One can cleanse the aura using nothing more elaborate than breath, just using the outbreath to send any unwanted energies through the grounding cord . This is fast and subtle, so it can be used anywhere, anytime.
The aforementioned violet flame is another effective way to cleanse the aura of negative energies. It transmutes such energies to a higher vibration.
After the aura is cleansed, fill it with your own energy. This is usually a mixture of Earth energy pulled in through the grounding cord and Universal energy pulled in through the crown. Mix the two in the core of your being, and let this energy pour out your crown to fill your aura. Let it shine bright. This is you.
In general, an aura-hygiene program should be part of your routine on rising and retiring, just like washing your face or brushing your teeth. As a minimum, it would include grounding, centering, shielding, and running energy through your aura to cleanse it. Most people like to follow this with a period of meditation, and finish by ensuring the grounding and shielding are still strong.
Of course, you can utilise any of these processes in an elaborate form before ritual, or in a simple and subtle form at any time in the day when you feel scattered or besieged, or when you are about to start any sort of process with other people. You can't control how other people react to anything you say or do, but you can control how their reactions effect you. If you are grounded, you won't be swayed unduly by their reactions. If you are centered, you will be able to respond in a clear and focussed way. If you are well shielded, anything that is negative won't get into your being and make you want to react. If your aura isn't cluttered with other people's energy, your response will be based in your own Truth, not a whole lot of responses you have been taught by others.
Taking control of your energy body is the first step to taking authority in your own mind and emotions. It is one of the first steps to claiming your power as a healer or worker of magic, or indeed as a individual.