Silk comes from silkworm or caterpillars which feed on mulberry leaves. After forty five days of raising with special care in feeding, cleanliness and temperature, they begin to produce cocoons of silk. Fully mature cocoons are boiled to separate amazingly tough silk filaments (Native Thai silkworm can breed all year round and produce yellow cocoons)Skeins of silk yarn are bleached before begin dyed and woven. Different kinds of bleach and bleaching methods are used by local weavers.