Proverbs 25:4
"Take away the dross from the silver, and there shall come forth a vessel for the finer."
Cross References (ranked by relevance)
Proverbs 17:3
The fining pot is for silver, and the furnace for gold: but the LORD trieth the hearts.
Ezekiel 22:18
Son of man, the house of Israel is to me become dross: all they are brass, and tin, and iron, and lead, in the midst of the furnace; they are even the dross of silver.
1 Peter 1:7
That the trial of your faith, being much more precious than of gold that perisheth, though it be tried with fire, might be found unto praise and honour and glory at the appearing of Jesus Christ: