You mean the energy that was left on the object from the person. Someone else's aura doesn't attach itself to an object. An aura would not stay on the object. The energy from the person would. Auras are personal as they are directly attached to the chakra system. We leave energy traces but those have nothing to do with an aura. Auras are just the energy we radiate from our body. That is why the aura would not attach itself to an object. You can't get rid of an aura but you can get rid of the unwanted energy that is on the object.
Just cleanse the item. To cleanse a ring, you could sit over a bowl of sea salt or you can rinse it over cold running water.