Blood Swallows from Luzon are excellent and expensive. In general, the ones there in Thailand are good. The good ones are usually at 80$/g. The identification methods are as follows: 1. Bird's nest should be filamentous structure, and the one made up of pieces of block structure is not the real bird's nest; pure bird's nest, no matter when it is soaked or viewed under the light, is not completely transparent, but translucent.

2. Smell: Bird's nest has a unique fragrance, but no strong odor. The special odor, fishy or greasy taste is fake;

3. Touch: Take a small piece of bird's nest to soak in water, soften it and then take the silk strip to pull it, the elasticity is poor, and it will be broken as soon as you pull it for the fake; rub it with your fingers, and it will be fake without any elasticity to be rubbed to a paste-like shape.

4. Burning: Use fire to ignite the dried bird's nest slices, if it is a real bird's nest, it will never produce any violent sound of splashing sparks

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