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, with an ethanol concentration of, say, about 20%-30%, some (about 2%-3%) alcohol ethoxylate (a surfactant) and a slightly basic pH (between 7 and 8), really ok to spray on a cold aluminum AC evaporator coil without fear of any damage at all? Or should an alcohol-free cleaner be preferred in any case for that job?
I think that the real concern for such a reaction would come in applications where alcohol is kept in constant/prolonged contact with aluminum or other metals susceptible to alcohol corrosion (i.e. alcohol stored in a non-lined aluminum container), since the little alcohol volume that is conveyed by the cleaner probably evaporates before any corrosion can (very slowly, at the temperatures usually involved) happen, especially if the blower fan is turned on shortly after as instructed. And i also think that evaporators are somewhat treated to increase their corrosion resistance anyway, because mold can apparently corrode the coils too.