Don't ever put aluminum in an ultrasonic cleaner. The frequency destroys the metal at the molecular level. Might be good if you're looking for a very permanent antique finish .... just don't leave it in too long or it will look like swiss cheese.
good to know!. before i asked the question i boiled it and it totally ruined the polish. looked like dull pot metal. I had to re polish the whole thing. the thinner and toothbrush worked amazing after that though!