Elemental boron is used as a rocket fuel igniter and in pyrotechnic flares generating a characteristic green colour: ‘Green flare compositions’ (1980).
The boron compounds boric (or boracic) acid, borax (sodium borate) and boric oxide can be found in eye drops, mild antiseptics, washing powders and tile glazes. Borax was used to make bleach and as a food preservative.
The cockney rhyming slang for having no money is “boracic lint” or just “boracic” meaning “skint”.
Boric oxide is also commonly used in the manufacture of borosilicate glass (Pyrex). It makes the glass tough and heat resistant. Fibreglass textiles and insulation are made from borosilicate glass: ‘Aluminium-free Borosilicate Glass’ (2018).
Sodium octaborate is a flame retardant: ‘Solutions for wood treatment and their preparation’ (1996).
The isotope boron-10 is good at absorbing neutrons. This means it can be used to regulate nuclear reactors: ‘Improvements in or relating to nuclear reactor control rod materials’ (1961).
Boron trifluoride is used in neutron detectors: ‘Neutron Counters’ (1971).