During a vanquish, beings are often destroyed in a violent, painful manner. Most vanquishes leave no trace behind and do not damage the surroundings or objects near the destroyed being. This is presumably in order to cover up any existence of magic from the mortal world.
Methods for Vanquishing
Vanquishing can be achieved by various means. The most common method of vanquishing is shown to be through the usage of spells. However, some demons can be vanquished merely by offensive powers, such as pyrokinesis, and ordinary or magical weapons. The weapons used could be anything from a dagger/knife to seemingly ordinary substances, such as baking soda or rat poison.
Some evil beings require a specific spell, sometimes requiring the Power of Three, while others may require a specific object or weapon, such as Viralis only being vanquished by his own dagger at the hands of a Charmed One. While most vanquishes are usually instantaneous, there are cases in which the entire process can take time if the being is upper-level (such as when Taydeus took a few seconds to explode after he died or when the spell to vanquish Lainey, the queen of the Cicada Demons, was slow causing Macy Vaughn to have to crush her with a control panel).