Alum powder, found in the spice section of many grocery stores, may be used in pickling recipes as a preservative to maintain fruit and vegetable crispness. Alum is used as the acidic component of some commercial baking powders.
Powdered alum can be used for treating canker sores. Simply, take a pinch of the powder in 2 spoon water and gargle it for approx 5 minutes can be helpful to bring down the pain and heal up the sores quite fast.
As an aftershave: it is being used as an aftershave for centuries. Take some alum powder and rub it thoroughly all over the freshly wet shaved face. Its astringent qualities will control bleeding from small shaving cuts and thus, prevent infection
For purifying water: when a small amount of alum powder is added to water, then the small particles of pollutants present in water tend to stick together and form colloid particles. Since colloid particles are heavy, they easily get settled down at the bottom of the container and the purified water can thus be strained out. Many people living in rural areas use this method to obtain clean water since ages
For reducing body odor: it can control body odor. It can be applied directly to the perspiring areas of the body. As it is soluble in water, it mixes up with the sweat and stops the growth of bacteria that causes body odor. It can be helpful for those who suffer from the problem of foot odor should apply it on their feet regularly before going to bed to get relief from it
Alum in the form of potassium aluminum sulphate in a concentrated bath of hot water is regularly used by jewelers and machinists to dissolve hardened steel drill bits that have broken off in items made of aluminum, copper, brass, gold, and silver (both sterling and fine)