Ammonium aluminium sulphate

Ammonium alum is not a major industrial chemical or a particularly useful laboratory reagent, but it is inexpensive and nontoxic, which invites many niche applications. It is used in water purification, in vegetable glues, in porcelain cements, in deodorants and in tanning, dyeing and in fireproofing textiles.^[4] The pH of the solution resulting from the topical application of ammonium alum with perspiration is typically in the slightly acid range, from 4 to 5.^[5]

Ammonium alum is a common ingredient in animal repellant sprays.^[6][7][8]