Is an alcohol-based spray cleaner ok for cleaning an aluminum heat exchanger? Simple alcohols such as ethanol can, apparently, corrode aluminum. However, this corrosion reaction seems to be very slow at room temperature and below. Is an ethanol based, non-foaming spray cleaner, propelled by LPG and with an ethanol concentration of, say, about 20%-30%, some (about 2%-3%) alcohol ethoxylate (this acts as a surfactant) and a slightly basic pH (between 7 and 8), really ok to spray on a cold parallel-flow type heat exchanger without fear of any damage? Or should an alcohol-free cleaner be preferred in any case for that job?

My belief is that the corrosion can only happen when the aluminum object is actually submerged in pure alcohol. That little alcohol conveyed by the spray probably evaporates before having the chance to do any damage, but i'd like to understand the surfactant role better, i.e. if any added surfactant agent can act as a corrosion inhibitor.
When aluminum metal is exposed to the oxygen of the air at room temperture, it forms a protective air-tight layer of aluminum oxide. So as long as nothing is present that will disrupt the oxide layer on aluminium it is OK for aluminium at 20 oC to be in contact with air.

If an aluminium alkoxide is exposed to water then the aluminium alkoxide will react with the water to form aluminium oxide and the alcohol. So in alcohol which contains some water it is not possible for the aluminium to dissolve in the alcohol.

But if the alcohol is anhydrous then it will be able to enter a scratch in the aluminium and start to react with the metal thus causing corrosion. For titanium that anhydrous methanol is very corrosive.

So as long as some water is present and air is present then at room temperture