Used as a cleaning agent for removing rust, ink stains, and oxides from metal surfaces, particularly iron and stainless steel, due to its ability to form soluble complexes with iron. Commonly applied in household, laundry, and industrial settings for metal surface treatment, preparing surfaces for plating or painting, and restoring rusted tools. Also effective in removing water-induced rust stains and yellowing on fabrics or other surfaces.

Employed in beekeeping to control parasitic mites (Varroa destructor) in honeybee colonies through careful application methods such as spraying or dabbing.

Utilized in the textile industry for dyeing and bleaching processes.

Used in the wood industry for bleaching to restore aged, weathered, or stained timber (e.g., black stains from water or metals) to a lighter, even color; popular for repairing furniture or wood floors.

Plays a role in rare earth element processing by precipitating oxalate salts during extraction and purification.

However, oxalic acid is highly toxic if contacted or ingested; handle with caution and strictly follow safety measures.