《资治通鉴·齐纪·齐纪三》
到了元狩中期，才开始改正这种弊病，于是，铸制了五铢钱，周边凸出，使人无法磨取铜屑，同时，五铢钱的铸制工本费高，铸制费用与使用费用相互抵消，不能获利，所以，民间偷偷铸钱的人也就越来越少了。这就是不吝啬铜和不惜精工铸造的效果。
至元狩中，始惩其弊，乃铸五铢钱，周郭其上下，令不可磨取鋊，而民计其费不能相偿，私铸益少，此不惜铜不爱工之效也。
It was not until the middle of the Yuan Dynasty that this evil was corrected, and the five-zhu coin was cast, with a convex periphery, making it impossible to grind off the copper filings. At the same time, the cost of casting the five-zhu coin was high, and the cost of casting and the cost of use offset each other, so there was no profit, and therefore, fewer and fewer people in the民間偷偷铸钱。This is the effect of not being stingy with copper and not being afraid to cast with precision.