Avoid aluminum alloys when working with vinegar solutions!
With time, the pH effect of acetic acid can penetrate the protective oxide coating. The exposed Al will even react with water:
2 Al (s) + 6 H2O (l) --> 2 Al(OH)3 + 3 H2 (g)
and with the presence of alloy metals, galvanic corrosion (especially if the 'dirt' is rich in salts that can serve as a good electrolyte) which apparently accelerates the attack on the Aluminum.
To quote a source:
corrosivity environment for aluminium in food industry are foodstuffs with pH 3 – 5, such as fruit juices, jams and acidic canned fruits or hot gravies, sauces as well as dressings, vegetables and fish pickled in brines with 1 –3 % salt . In particular, acetic acid needs to be taken into corrosion consideration, due to its wide usage in food industry (vegetable and fish pickling), and its representative properties among acids and juices in fruits, vegetables and other organic materials that can corrode metals. Although aluminium has a good resistance to acetic acid solution at room temperature, aluminium can corrode in almost any concentration of acetic acid at any temperature if the acid is contaminated with the proper species .
Further comments related to the presence of select metals:
Although aluminium has a good resistance to almost all the concentrations of acetic acid at room temperature, care must be taken that the metal is free of other impurities such as iron, copper, tin and lead even in traces . With increasing purity of aluminium, its resistance to acetic acid solution increases, and 99.5% aluminium can be used for the majority of engineering purposes, but components added to its alloy can increase the corrosion of aluminium in acetic acid solution . Since the metal corrosion occurs via electrochemical reactions at the interface between the metal and an electrolyte solution, electrochemical techniques are ideal for the study of corrosion processes.
And importantly, the effect of pH:
It is well known that aluminium resistance is related to the thin and compact layer of naturally formed oxide on aluminium surface, but this oxide layer is stable only in pH range 4-8. Lower or higher pH values caused prominent destroying of protective layer and thus the significant metal dissolution .