how to clean up old junkyard oxidized aluminum parts?

hard mode.. this is not a blastable part..

Recently purchased a older STI intercooler. It has pretty straight fins and is all there.

But the finish on the alunimum is crap. Most likely sitting for a decade. or the salt boat ride over from japan got to it.

its white and scaly on the cast end tanks.   I need something i can spray on and rise off that will remove the oxidation and powdery finish but not eat a hole through the part.

Thoughts at this point are A/C coil cleaner. or some type of muraic acid like i used to etch the floor of the garage before putting down the coatings. 

maybee some specific wheel cleaner with enough UMPHF to cut the crud.

Thanks in advance. 

phosphoric acid

This is the main chemical in "Lime Away" also used when etching concrete.

You can buy a gallon of it for around $10-15.

Dilute it 3-4 parts water to 1 part acid.

IF you can soak the part in the solution it's best, other wise just keep it "wet" using a spray bottle with the solution.

It won't make it like new but it will clean the aluminum. Don't use muraic acid as it will "eat" the aluminum.

NAPA sells a product called aluminum brightener that works well, you can get similar products from other auto parts stores.  It does contain phosphoric acid among other things, so you need to take proper precautions and wear protection when using it.