Gold Cleanup

Finding gold is only half the job. At the end of a day of panning or sluicing you are left with a pile of heavy, dark concentrate, and somewhere in it is your gold. Getting it out cleanly is called cleanup. This page explains what cleanup is, how to do it with a pan and with a sluice, where a magnet fits, and what to know about cleaning and melting gold. The guides listed below go into each step.

What is gold cleanup?

Cleanup is the final pass that turns concentrate into gold you can put in a vial. A California state report on placer gold recovery splits the work into three stages. Roughing is the first pass that catches the heavy material, like a sluice or your first rounds of panning. Cleaning is going back over that rough concentrate to get rid of everything that is not gold, and the report notes that this can be as simple as washing black sand in a gold pan. Scavenging is a last pass over the leftovers to catch anything that slipped through.

The same report sums up the goal well: the best systems keep as much gold as possible in as little concentrate as possible. Every step of cleanup is about shrinking the pile without losing the gold.

It matters most in gold country like California, where the same report says over 64% of the state's gold has come from placer deposits, the loose gold found in stream gravel.

How do you clean up the concentrate in your pan?

Pan it down, take out the magnetite, give it a quick final pan and pick out the gold. The U.S. Forest Service and Bureau of Land Management describe the same finish in their guide to recreational gold panning, and Oregon's state geology department gives nearly the same advice: lift out most of the black sand with a magnet, then separate the gold from what is left.

1. Work over a second container. Do your final panning over a tub or another pan, so anything that slips over the edge can be panned again.
2. Pan down to the black sand. Wash off the light material until only the dark, heavy concentrate is left in the bottom of the pan.
3. Lift out the magnetite. Leave a little water in the pan and pass a magnet slowly over the concentrate. In a normal pan, our magnet pulls up all the black sand we see. Some panners dry the concentrate first and run the magnet over it dry, and that works too. Keep the magnet away from steel tools, phones and cards, and read our magnet safety warnings.
4. Check what the magnet lifted. A magnet does not pull gold, but a tiny flake can ride along stuck to a grain of magnetite. Drop the magnetic sand into a pan of water and look it over before you toss it.
5. Give it a quick final pan. With the magnetite gone there is far less to wash. Swirl gently and the gold stays behind while the leftover grains move aside.
6. Pick out the gold. Use tweezers, the tip of a knife, a dry fingertip or a snuffer bottle.
7. Store it in water. Keep your gold in a small vial filled with water, where it is easy to see and hard to spill.

Our guide to separating gold from black sand goes through the magnet step in detail, and How to Use a Snuffer Bottle covers picking up the flakes. A black sand magnet is the tool for step 3.

How do you clean up a sluice?

You wash the gravel out, then collect everything caught in the riffles and mat and pan it down. California's state report lists the basic steps, which come down to this:

1. Run clear water. Keep water flowing with no new gravel until the riffles are free of loose gravel.
2. Set a catch container. Put a pan or bucket at the outlet end of the sluice.
3. Take out the riffles. Start at the head of the sluice and rinse each riffle section back into the sluice as you lift it out.
4. Wash the mat separately. Rinse any mat or bottom lining into its own container, since that is where much of the gold sits.
5. Pick out the big pieces. Any large gold you can see can come out by hand.
6. Collect the concentrate. Wash what is left into a container, then clean it up with a pan as described above.

Clean up often. The same report cites a dredge study in which gold recovery was 90% when the sluices were cleaned every 12 hours and 94% when they were cleaned every 2 hours. That was a commercial dredge, not hobby gear, but the lesson carries over: a sluice that sits full for too long starts to lose gold.

What about gold cleanup machines?

For a few pans of concentrate, a pan, a magnet and tweezers are all you need. People with buckets of concentrate sometimes use machines to do the panning for them.

The common hobby machine, often called a gold wheel or automatic panner, is a spinning, tilted plate with a spiral molded into it. California's state report describes how it works: water washes the light material over the lower edge while the spiral carries the heavy concentrate up to a hole in the center. It describes spiral machines in general as catching heavy minerals from about 3 mm down to 75 microns. Shaking tables are another cleaning machine, used on concentrate rather than raw gravel.

Some panners also use water-swirl bowls, often called blue bowls, or small cleanup tables such as the Miller table. We found no official source that tests them, so we simply note that some panners use them and give no recovery figures.

How do you clean raw gold?

Start by knowing what you are cleaning. Gold does not rust or tarnish, so if a piece looks dull, something is on it or its surface is worn. Oregon's state geology department notes that some placer gold is coated with iron oxide, which can hide its color. Years of knocking around in a creek also leave most placer gold with a rough, pitted face rather than a polished one.

We have not found an official source for any chemical cleaning recipe, so we do not give one. Never use mercury on your gold or your concentrate. It is a serious health hazard, and California's state geologists named that hazard as the biggest drawback of using it.

Can you melt gold at home?

Melting is the very last step, after cleanup, and it is hot, risky work. This page does not give melting steps. Randy has melted gold himself, but here we stick to the safety and legal facts.

How hot does gold melt?

About 1,064 °C, which is roughly 1,947 °F, according to the National Park Service. That is far hotter than anything in a kitchen.

What are the main dangers?

Water is the big one. Federal safety officials at OSHA call steam explosions from water meeting molten metal a well known hazard, and wet concentrate, damp tools or a damp mold can all carry water. Federal workplace rules also require eye or face protection for anyone working around molten metal, so even professionals do not do it bare faced.

Never heat concentrate that might hold mercury, which old diggings sometimes do. Heating it turns the mercury into vapor, and the EPA warns that this can be very dangerous. Pyrite, the most common fool's gold, does not melt like gold either. Oregon's state geology department notes that it gives off sulfur fumes when heated.

Should you melt black sand to get the gold out?

No. Separate the gold from the black sand first, with a pan and a magnet. Melting is for gold that is already clean.

Does melting make gold pure?

No. Natural gold is always mixed with some silver and other metals, and melting it does not take them out. A melted button of placer gold is still that same mix. Refiners and assayers are the ones who measure how pure it is.

Is it legal to own and melt gold?

Owning gold is legal. Americans have been free to buy, sell and own gold since a 1974 law, Public Law 93-373, took effect on December 31, 1974. We found no federal rule about melting gold at home, so check your local fire and air rules before you try.

Where should you start?

If you are new to cleanup, start with How to Separate Gold from Black Sand, since black sand is most of what you clean up. To be sure that what is left in your pan really is gold, see what gold flakes look like. If your gold is very fine, our fine gold recovery guide shows how to keep it. Every cleanup guide we publish is listed below.