I had a Mr. Misto and found the solution to clogging. Before you refill it with more oil, fill it with hot soapy water. Pump it up and spray a couple times, then rinse and refill with with plain hot water. Spray again, to get all the soap out of the mechanism.
Refill, pump it up and spray for a few seconds into the sink to clear the water out.
I just haven't been the same
since that house fell on my sister.