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Cleaning tiny aluminum car parts

Hi all

I'm trying to clean cast aluminum parts that are very small and have hard to get to spots on them.Thay have gone dark gray and black in some spots I was told to use castic soda but tried that on a bit of scrap and it went black.

I can't get into the small spots to polish so what to do ...?

Please help any info would be good.

Thanks mark.

Mark Hinson
eze10s performance car racing - Sydney, NSW, Australia
2004

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Caustic dissolves aluminum but not the alloying materials; and when it does those materials left on the surface are finely divided and look black. Caustic should not be used to clean aluminum but if it is, the aluminum must be 'desmutted' in powerful oxidizing acids like nitric acid or chromic acid mixtures. This is dangerous stuff that should be best kept in an industrial environment. Any anodizing shop can do this for you.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004

For just cleaning dirt, look at getting a [on eBay or Amazon]. They sell some very small ones at a rational price for home use. They are cup sized, plug into the wall outlet and hum when turned on. For solvent, alcohol works well, alcohol and water will remove some organic and some inorganic material. Most soap solutions will bubble or foam a bit (possibly too much). If you wonder why it works so well, look up a web site on ultrasonics.

James Watts
- Navarre, Florida
2004