The term "exorcism" as defined by Ciro Discepolo is borrowed from psychoanalysis. It was originally called "constellation of the symbol" where "constellation" means: activate the symbol, live it, put it on stage. Just as in the family constellations, the therapy developed by the german psychologist Bert Hellinger, the family system is put on stage, because the psychologist says that certain dynamics can only be solved through a dramatization of your family constellation.
And astrologically speaking, what we must activate, live, put on stage? The symbol obviously represented by the planet transiting through a house or in aspect to a planet of our birth chart, even more so if it is an important transit, often heavy as in the case of Mars, Saturn, Uranus, Neptune and Pluto. So what do we have to do? What does Active astrology advise us to do? To be "pro-active", creating favourable environments where the symbol can be expressed in all its power, before that transit and its symbol find a way to express themselves, often in a painful way.
The greater our willingness to consciously live the archetype that the planet represents, choosing to meet those situations which are in tune with that archetype, going in the direction expressed by the symbol, the lower the probability that it will find alternative channels to express itself often in a destructive way.
Here are examples of how you can exorcise the symbol represented by the planet, noting that the technique can be used for both a planet transiting and for a planet that occupies a particular house in your Solar Return chart.