Editing Alum (section)

==Uses==

=== Industrial processes ===
Aluminium-based alums have been used since antiquity, and are still important for many industrial processes. The most widely used alum is [[potassium alum]]. It has been used since antiquity as a [[Clarifying agent|flocculant]] to clarify cloudy liquids, as a [[mordant]] (or binder) in [[dyeing]], and in [[tanning (leather)|tanning]].  It is still widely used in [[water treatment]], for medicine, for cosmetics (in [[deodorant]]), for food preparation (in [[baking powder]] and [[pickling]]), and to fire-proof paper and cloth.

=== To stop bleeding ===
Alum is used as a [[styptic]] (to stop bleeding) in styptic pencils available from pharmacists. Alum blocks, available from barber shops and gentlemen's outfitters, are used to stem bleeding from shaving nicks;<ref name="Blake-Blade-2020-01-11-shaving-Alum" /> and as an [[astringent]]. 

Powdered alum are also used in Southeast Asian traditional medicine for open wounds and sores.<ref name="Chaudhury-Rafei-2001" /><ref name="Emocling-c2018" />

=== Deodorant ===
[[File:Tawas (alum), a traditional deodorant in the Philippines 01.jpg|thumb|{{lang|tl|Tawas}} (powdered alum crystals), a traditional scent-less [[deodorant]] for underarm and feet odor in the [[Philippines]] and most of [[Island Southeast Asia]]]]

An alum block can be used directly as a perfume-free deodorant (antiperspirant), and unprocessed mineral alum is sold in Indian bazaars for that purpose. Throughout [[Island Southeast Asia]], potassium alum is most widely known as ''tawas'' and has numerous uses. It is used as a traditional antiperspirant and deodorant. The crystals are usually ground into a fine powder before use.<ref name="Chaudhury-Rafei-2001" /><ref name="Emocling-c2018" />{{Better source needed|reason=The cited sources are insufficient: <ref name="Chaudhury-Rafei-2001" /> is a WHO report on alternative medicines that only tangentially mentions tawas as a body odor reliever, and <ref name="Emocling-c2018" /> is a blog post that itself states alum or tawas "doesn't stop us from sweating." Medically backed sources on its effectiveness and safety as an antiperspirant and/or deodorant should be provided here.|date=September 2024}}

=== Bread ===
In Britain alum has been used as a way of preserving [[flour]] and bleaching it. Bakers used small amounts to make the fine white [[manchet]] bread produced for the rich. In times of poor harvest, more alum was added. In 1758 the British government banned the use of alum in bread, although some bakers continued to use it and many people continued to demand white bread adulterated with alum.<ref>{{Cite book |last=Norman |first=Jill |date=2024 |title=The English Table - Our Food Through the Ages |location=London |publisher=Reaktion Books |isbn=978 1 78914 933 3 |publication-date=2024 |page=114 }}</ref>

During the 19th century, alum was used along with other substances like [[Plaster|plaster of Paris]] to adulterate certain food products, particularly bread. It was used to make lower-grade flour appear whiter, allowing the producers to spend less on whiter flour. Because it retains water, it would make the bread heavier, meaning that merchants could charge more for it in their shops. The amount of alum present in each loaf of bread could reach concentrations that would be toxic to humans and cause chronic [[Diarrhea|diarrhoea]], which could result in the death of young children.<ref>Phillips, Suzanne, director. [https://www.youtube.com/watch?v=j9gv5528JZQ ''The Hidden Killers of the Victorian Home'']. Sterling Documentaries, 27&nbsp;Jan. 2018. Accessed 9&nbsp;Oct. 2021.</ref>

=== Textiles and paper ===
Alum is used as a mordant in traditional textiles;<ref name=Crawfurd-1856/> For traditional [[Japanese art]], alum and [[animal glue]] were dissolved in water, forming a liquid known as ''dousa'' ({{langx|ja|[[:ja:礬水|礬水]]}}), and used as an undercoat for paper [[sizing]].

=== 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" />

===Other===
In the Philippines, alum crystals were also burned and allowed to drip into a basin of water by ''[[babaylan]]'' for [[divination]]. It is also used in other rituals in the [[animistic]] [[anito]] religions of the islands.<ref name=Dyrness-1992/><ref name=Hornedo-2000/><ref name=Mercado-1997/><ref name=Starr-1930/>