Plant seeds are beneficiated by contacting them with an aqueous solution of a urea-sulfuric acid component containing the monourea adduct of sulfuric acid. The molar ratio of urea to sulfuric acid in the aqueous solution is preferably within the range of about 1/4 to about 7/4 so that at least about 25 percent of the sulfuric acid is present in the solution as the monourea adduct. The treatment of plant seeds with the aqueous urea-sulfuric acid components is particularly useful for removing residual plant matter from plant seeds, scarifying and improving the germination of plant seeds, and improving the processability and digestibility of plant seeds. Improvements in processability result from softened seed hulls or husks, improved extractability of oil from oil-containing seeds, and improved quality of treated seeds for the manufacture of seed derived products, particularly for the manufacture of grain-derived products. Compositions which involve mixtures of plant seeds and the urea-sulfuric acid components are also provided.