Verse 74

न हेम तापशुद्धाङ्गं स्वभावमलमागतम् ।कर्दमे मग्नमपि सत्समादत्ते मलं पुनः

In plain words

Gold whose body has been purified by fire, having fully come into its own nature, does not take on dirt again, even when sunk in mud.