千万毛中选一毫——“四德”一体，方为良笔

先次以铁梳梳兔毫及羊青毛，去其秽毛，盖使不髯。茹迄，各别之。皆用梳掌痛拍，整齐毫锋端、本，各作扁极，令均调平好，用衣青羊毛。……然后合扁卷令极圆，讫痛颉之，以所整羊毛中为笔柱，复用毫青衣羊毛使中心齐，亦使平均，育颉管中……

Restrict Selection for Brush Material——Four Merits Achieve a Supreme Chinese Writing Brush

Firstly, we shall use iron comb to tease the rabbit and goat hair to make them neat. Secondly, we make the brush tips with processed hair. Thirdly, we form the brush pillar centered by goat hair and use rabbit hair to make brush pillar neat and plump. At last, we shall bundle up the hair and fit them into the bamboo stick to make a writing brush.