wrote in message
...
Ok, so I am an idiot. I pushed things too far and may have cost myself
a bit of money in the process. I work with beer equipment and had some
old brass draft beer towers that needed some love. One of the cleaning
chemicals I work with is hydrochloric acid and I've noticed that when
I use this on brass parts they shine. I think this may work on the
tower I have so I soak it in a solution of 7 oz. hydrochloric acid and
4 gallons of water overnight. First day it looks good, second day it
looks better, third even better, fourth day it is pink! What happened?
Is there anything I can do to restore the shine? Any help would be
appreciated because I would like to save this thing if I can. Thanks
in advance.

A similar thing happens when silver-brazing brass: the surface zinc
boils off leaving just copper on the surface.

A buffing wheel will restore the brass look. An automotive buffer
with rubbing compound might even work though it might take a while.
I've not found a chemical that will preferentially remove copper while
leaving zinc.