whit3rd fired this volley in news:45a8eead-9f88-4d08-
:

I've used TSP on aluminum, without problems. Lye, and washing soda
(OxyClean and such) are the aluminum (and aluminum/zinc alloy)
molesters.

Dilute lye can be used on it, too (for a time). Hot, concentrated TSP is
quite corrosive to aluminum; enough so that it's sometimes used as a
prep etch alone or in combination with other etchants, because it also
acts as a surfactant to wash the item clean after etching.

All sorts of things, actually, can vigorously attack aluminum because of
where it is on the electromotive series. Lest you think I'm crazy, let
me warn you that this is not obvious -- but water with a pH just barely
basic of neutral attacks aluminum VIGOROUSLY under certain circumstances;
so vigorously that it can cause substances to heat to the point of
ignition.

All of us pyrotechnics guys are aware of the dangers of water and
aluminum. There have been numerous fires, many burns, and a few deaths
because of it.

Lloyd