Aluminum acetate, for one, can also be ototoxic in a patient with a perforated drum.
In the study by Clayton et al, published in 1990, the authors compared the clinical efficacy of a topical gentamicin and topical aluminum acetate in 139 ears with otorrhea.
Acidifying solution--such as aluminum acetate, acetic acid/hydrocortisone, boric acid, glycerine-ichthammol, etc.--have been used over the years, certainly in developing countries.
Among the aqueous solutions are ordinary water, 10% sodium bicarbonate, 3% hydrogen peroxide, 2% acetic acid, and a combination of 0.5% aluminum acetate and 0.03% benzethonium chloride.