Bleaching or dying

There are four deceiving practices you need to know before you buy a bird’s nest from anybody else:
Bleaching or dying: The bird's nests either come from caves or houses that are specially built to accommodate them. The red-blood swallow nests get their distinctive color from the interaction of minerals, air, and humidity and are fairly rare. It is generally believed that the minerals in red nests are richer than those in white nests, so the price is slightly higher. However, there are some merchants using food coloring to dye the white nests red to achieve a higher price. This color processing also hides the presence of fine feathers and other particles that should be removed and can cause harm. White bird's nest is a natural product and it has its own natural greyish color. If you look at pure white or red nests, there is a high chance that they have been bleached with chemicals or dyed.  Often, consumers are misled by the idea that a pure white or red bird’s nest is of higher quality, which is not true. A natural white bird's nest should be cream or grey colored and can have some darker spots. A natural, unbleached bird’s nest should have a natural mildew aroma. If it doesn’t possess that smell, or contains a strong chemical odor, that is a sign that it had been bleached or dyed.