The process of making of seeds free from inert matter and defective seeds is

The process of making seeds free from inert matter and defective seeds is Physical purity.
It is the cleanliness of seed from other seeds, debris, inert matter, diseased seed, and insect-damaged seed. It also should be devoid of shriveled, diseased mottled, moulded, discoloured, damaged and empty seeds.
Physical purity testing refers to the analysis for classifying the composition of a seed lot. It is important for evaluating whether the given seed sample conforms to the prescribed purity standards.