why does john donne describe weeping as a mintage?How do the tears get coined and stamped? in poem " To say Good bye".

“A Valediction: of Weeping” begins with a scene of two lovers parting: Let me pour forth My tears before thy face, whilst I stay here, For thy face coins them, and thy stamp they bear, And by this mintage they are something worth The poet is asking for his lover’s indulgence. If he cries now, while he’s still with her, her “face” will be reflected in his tears, transforming them from ordinary waste into objects of value—“coins.” The poet isn’t asking for a physical connection here; he doesn’t say “embrace me before I go.” Instead he seeks to reflect and be reflected by the beloved, at once emphasizing their connection and the fact that they are already—even now before his departure—undeniably separate. Please check this source out: