Or pulverize the leaves and seeds of the paulownia tree then place them in a pot to boil. After boiling, wring the mixture through a new cloth. Using the resulting liquid to wash gray hair will blacken it. Tang dynasty writer Sun Si-mao's Golden Prescriptions also records that the liquid resulting from cooking black beans in vinegar can be used to dye one's hair black.
清朝《通天秘書》中也記載有白髮染黑的藥方：蝌蚪、黑桑椹各半斤，裝入瓶內密封，等百日化泥後，拿來塗鬚髮，可以「永黑如漆」，或者將桐葉及子搗碎，放在甑裡蒸煮，用新布絞汁，絞出來的汁液拿來洗頭可以使白髮變黑。