It can be processed all year round. Soak the donkey skin in clean water for about 2 to 3 days. After softening it, take it out and scrape off the donkey hair, cut it into small pieces, wash it with clean water, and boil it in boiling water for about a minute. When the skin is rolled up, take it out, put it into another pot with a lid and add water until the skin is submerged, and simmer for about three days and three nights. When the juice is thick, take it out, add water and cook again, repeat this 5 to 6 times, until until most of the colloid has dissolved. Filter the resulting juice through a fine copper wire sieve, add a small amount of alum powder to the filtrate, stir, and let it sit for several hours. After the impurities precipitate, collect the upper solution and heat and concentrate. Add flavoring and flavoring agents (1,000 kilograms of donkey skin plus 7.5 kilograms of rice wine and 15 kilograms of sugar) 2 hours before glue is produced. Add soybean oil (1,000 kilograms of donkey skin and 15 kilograms of sugar) half an hour before glue is produced to reduce the glue content. The stickiness. Use a spatula to pick up the glue and stick it together until it no longer falls into the pot. Put it into a wooden plate lined with lead skin. Apply soybean oil on the lead skin in advance to avoid adhesion. When the glue solidifies, take it out and cut it into small pieces. The piece is 10 cm long, 4 to 4.5 cm wide, and 1.6 cm or 0.8 cm thick. Put it on a wire rack to dry, turn it every 2 to 3 days to avoid unevenness on both sides. After 7 to 8 days, place it neatly in a wooden box, seal the box and flatten it. After the skin softens, take it out and spread it out to dry. Stuff it again and then dry it (you can also use blast drying method). Before packaging, wipe off the outer surface with a damp cloth, and you have the finished product.