It depends on whether the aura is the result of something more serious or is just an effect which is stuck in on mode.

So long as the Sim in question is a member of the household, you can try the standard trick for resetting stuck effects.

If you have Insimenator, spawn the Deleter and delete the Sim. Then delete the Deleter.

If you don't have Insimenator, open a cheat box and type in:

moveobjects on

Then press the Enter key to initiate the cheat.

Then go into Buy mode, click on the Sim and delete him/her.

Open the cheat box again and type in:

moveobjects off

Then press the Enter key to initiate the cheat.

This is safe -- the Sim is not in any way gone forever.

Once the Sim is no longer there, exit to Neighborhood (yes, Save the game).

Then when you re-enter the lot, the deleted Sim will be back, standing by the mailbox.

If the aura is gone, then it was just a stuck effect and all is now normal. If the aura is still there, then it is related to (and re-generated by) some other action or case.

If the Sim is not a member of the household, you can do the same thing, but that Sim will not be returned to the lot when you re-enter it.

Don't have the EP with the genie so can offer no guidance relating to that but have had to do this many times, such as when a child who has been blowing bubbles keeps generating bubbles after he/she is done, or when a Sim's arm sometimes gets frozen in a single odd position (which seems to happen particularly to Vidcund Curious on a regular basis).