First of all, the bird's nest is a nest produced in Jin Siyan, and the bird's nest that has just been picked will inevitably be polluted by the environment, with impurities such as eggshell fragments, small black spots and swallow hairs. It is necessary to clean the bird's nest with pure water, and at the same time, gently brush the surface with a soft brush and carefully pick the hair to become a finished bird's nest. Therefore, a good bird's nest must be a pure natural bird's nest that has been manually cleaned and picked. The quality of bird's nest in Tongrentang and Fulinmen is very good. In fact, the choice of bird's nest, good bird's nest, no matter where it is produced, must have a high dryness, and it will be broken if it is slightly folded. The higher the dryness, the easier it is to store, and it will not be moldy when sealed in the shade. Besides, a good bird's nest tastes like an egg after being stewed, because it is made of swallow's saliva and is rich in protein's bird's nest acid. If the taste is a little pungent or musty, it is the problem bird's nest. High-quality strips are generally more than 6 times, and some can even reach 8-9 times, depending on the quality of bird's nest, soaking time and technology. The inferior bird's nest, after being treated with liquid medicine or brushing glue, makes the texture of bird's nest destroyed, and it is not easy to foam, and the hair is small, and some even can't foam at all.