The Collaborative International Dictionary
Corroding lead
Corrode \Cor*rode"\, v. i. To have corrosive action; to be subject to corrosion.
Corroding lead, lead sufficiently pure to be used in making white lead by a process of corroding.
Syn: To canker; gnaw; rust; waste; wear away.
Wiktionary
corroding lead
n. Lead (the metal) that is sufficiently pure to be used in making white lead by a process of corrode.