Editing Alum (section)

=== Jewellery ===
In [[Indonesia]] and the [[Philippines]], solutions of ''tawas'', [[salt]], [[borax]], and organic pigments were used to change the color of [[gold]] ornaments.<ref name=Villegas-2004/> 

Alum in the form of [[potassium aluminium sulphate]] or [[ammonium aluminium sulfate]] 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 (any karat), silver (both sterling and fine) and stainless steel. This is because alum does not react chemically to any significant degree with any of these metals, but will corrode carbon steel. When heat is applied to an alum mixture holding a piece of work that has a drill bit stuck in it, if the lost bit is small enough, it can sometimes be dissolved or removed within hours.<ref name="Lee-2013" />