# How to dissolve brass surrounded by aluminium?

I have a broken off brass needle stuck in a caste aluminum hole. (It’s the pilot mixture jet on a carburetor).

I was wondering if there was a chemical that would dissolve the brass while not reacting to the aluminium.

Previously I’ve tried:

• Using thermal expansion and contraction to loosen it.
• Attempting to poke it out.
• Using an air compressor to blow it out.
• Concentrated nitric acid will dissolve common brasses, but not aluminum. But, even if it works well, it would be slow going for a needle in a small hole. Good luck!
– Ed V
Jun 19 at 0:39

Not likely. Ammonium hydroxide will attack brass, but at high concentrations and not very fast. And worse, I don't easily find data for aluminium in concentrated $$\ce{NH4OH}$$, probably because it has poor resistance.