The paper provides a review of fractional technologies developed by the authors, allowing to divide the grain heap coming from combines into 3 fractions: seed, fodder and unused waste. They are based on the use of two-aspiration air-sieve grain cleaning machines. The authors have developed a line of grain cleaners OZF-50/25/10 and OZF-80/40/20. Their productivity in terms of preliminary cleaning is 50 and 80 t/h, primary cleaning productivity is 25 and 40 t/h and secondary cleaning productivity is 10 and 20 t/h, respectively. The machines use an improved two-aspiration system with the ability to independently adjust the speed of air flows in the channels (patent No. 2298441), a new design of a sieve mill with a two-tier arrangement of sieves and setting in each tier sequentially two (at OZF-50/25/10) and three (on OZF-80/40/20) sieves. The mills implement a new sieve arrangement scheme (RF patent No. 43798), as well as original devices for a ball sieve cleaner and a pneumatic separation channel for the second aspiration. These devices make it possible to obtain the required quality of sieve cleaning and to isolate biologically defective grain in the pneumatic separation channel of the second aspiration. The separator for secondary cleaning of seeds SVS-30 is designed for the preparation of seeds of grain, spike, leguminous, industrial and oil crops when implementing fractional technology during post-harvest processing. Like all machines for secondary cleaning of seeds, the pneumatic system of the separator has two pneumatic separation channels for pre-screening and post-screen cleaning. A distinctive feature of the pneumatic system of the SV-30 separator is the consistent use of the same air flow in both aspirations. Fractional technology for processing grain heaps, implemented on an air-sieve separator, will increase the cleaning performance by 1.5…1.8 times with a minimum amount of mechanical stress on the seeds.