# Can I use piranha solution to clean copper out of impurities?

I have some old pieces of wire. Since I want to use copper in homemade fireworks, I'm trying to gather it from the wires. I could buy it, however harvesting is much more fun.

Sulphuric acid doesn't dissolve copper in normal conditions, even when it's concentrated. However adding $\ce{H2O2}$ causes vigorous reaction during which copper sulphide is created.

On the solution surface, remains of impurities are floating. I'm afraid, however, that most of impurities were dissolved. Were they?

I don't need my $\ce{CuSO4}$ chemically clean, but too much impurities could increase the risk of toxic gases during electrolysis.

• The difficulty here is that you've almost surely got excess peroxide and sulfuric acid in your solution, and it's going to be a challenge to eliminate them in a safe way in your kitchen/garage without resorting to something more expensive than just buying the chemical you want to make or producing a toxic byproduct. If I were going to do this, I would just buy a couple of pounds of copper sulfate. It's sold at home improvement/hardware stores as root killer in high purity form for very little money. – Jason Patterson Oct 1 '14 at 4:21
• This way I could just buy copper dust as well, since that's what I need. No, I'm really trying to purify it. – Tomáš Zato Oct 1 '14 at 5:01