To increase their strength and smoothness the leads are then treated with a hot mixture which includes candelilla wax from Mexico, paraffin wax, and hydrogenated natural fats.

• 为了提高其强度和顺滑性，还要用一种滚热的混合物处理铅笔芯，其中包括固体石蜡、经过氢化处理的天然脂肪和产自墨西哥的大戟石蜡。