From Dow Product Safety:
Roughly 75% of the available acetone is used to produce other chemicals, and 12% is used as a solvent.
Applications range from surface coatings, films and adhesives to cleaning fluids and pharmaceutical applications.
Other consumer and commercial applications include:
Lacquers for automotive/furniture finishes
Cellulose acetate films and fibers
Photographic films and plates casting
Coatings and inks
Resin thinners and clean-up operations
General purpose cements
Degreasing and degumming agents
Paint, varnish, lacquer strippers
Nail polish removers
Various cosmetic products
Of course, that leaves out any illicit uses or illegal disposal of chemicals.
Acetone and ethyl acetate volatalize readily at room temperature and volatalize almost completely (no residue). They are great solvents and, because they are minimal chain organics, very few organic surface treatments (paint, polish, dyes) are insoluble in their presence (they strip just about everything). Smelters might use them for oil/grease removal but I doubt it given their flammability profiles.
I pointed out the smelters because the student said they (1) had a metallic taste in their mouth (another culprit might be sulfur compounds from somewhere) and (2) smelled the odor “+like+ nail polish remover” which means an organic solvent of some type.
Smelters would certainly use cold-dip degreasers which would involve a large tank of chlorinated solvents (non-flammable)