Swiftlets' nests, made from the feathers and hardened saliva of the bird, are one of the most prized delicacies in China. The nest soup Yànwô has supposed cleansing properties and a salty taste, owing to the bird's fish-based diet. The high price is due to the painstaking purification process needed to remove any trace of non edible substance (well, you know what we mean...) to make the ingredient healthy safe!

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