Grading shall be carried out according to the specification requirements of processing cans, and the mushroom bodies that are not suitable for full packaging, such as cracked cap, deformed cap, open umbrella and uneven color, shall be picked out, and the diameter of about 1.5cm is the first grade mushroom; The diameter of about 2.5cm is the second grade mushroom; The diameter of about 3.5cm is the third grade mushroom; Those below 4.5cm can be used for processing sliced mushrooms, and those with a diameter of more than 4.5cm can be used for processing shredded mushrooms. The tinned iron cans or glass bottles shall be strictly inspected before being filled, and the unqualified empty cans shall be removed. Then wash it in hot water at 90-95 ℃, put it upside down on a clean shelf and drain it for standby.