Turn lead into gold for the Alchemist

The king of the realm is facing a shortage in the treasury. His solution is therefore to add vast quantities of gold to it. However, raising taxes on a land of lead mines won't work. Instead, he has designated the town alchemist as the official gold maker. But the alchemist so far has not been able to figure out how it's done, and the patience of the king is wearing a bit thin. See if you can help Charles the Alchemist turn lead into gold.

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