Use household ammonia damage aluminum?
Yes, aqueous ammonia is likely damaging in time to metal Aluminum in the presence of air and any salts (from outside dust,...) that may further serve as an electrolyte. 

Ammonium salts, themselves are good in transporting solvated electrons, and here you are, unintentionally, likely creating a metal-air battery scenario. 

Possible half-cell reactions:

$\ce{ Al -&gt; Al(3+) + 3 e- }$

$\ce{ O2 + 2 H2O + 4 e- -&gt; 4 OH- }$ 

Resulting in a net cell reaction of:

$\ce{ Al(3+) + 3 OH- -&gt; Al(OH)3 }$

The aqueous ammonia may also assist here in the removal of the Aluminum hydroxide by forming a "dissolved/peptised/supersaturated hydrated alumina" (per a paper 'The Precipitation of Aluminium Hydrous Oxide and Its Solubility in Ammonia' by Prideaux and Henness).

In essence, Aluminum is now a more rapidly corroding anode. 

Nice experiment, albeit, unintended.