There's a semi famous trick of turning copper coins into silver and gold coins. Notice the word 'trick'? It's not actually real silver and gold but it gives a nice decorative effect.
For this trick you will need zinc sulphate which can be bought cheaply online. Or you can make it by dissolving zinc metal into sulphuric acid.
Drop in some zinc metal and a clean copper coin into a strong solution of zinc sulphate and bring it to boil for about 15 minutes. The zinc and copper must be touching. The coin will be coated in a layer of zinc metal which looks like silver.
To turn a coin gold you must first coat it in a layer of zinc, as shown above. Then you must heat it to about 300 degrees Celsius until the zinc and copper form a coating of brass. Drop in into some water to cool it down and it will have the appearance of gold.
Protip: This works on anything copper, so you can also make gold and silver bling.