Cleaning Rocks with Hydrogen Peroxide: A Beginner’s Guide

When it comes to cleaning rocks, the rockhounding community advises suggests more ways (and products/strategies) than someone new to the hobby can sift through.

Many of the suggested products sound like they would be more at home in a chemistry lab than in a hobbyist’s garage.

In this article, we’ll talk about what you need to know when trying to clean your rocks with hydrogen peroxide.

What Does Hydrogen Peroxide Clean?

In general, rockhounders use hydrogen peroxide to remove black and brown manganese stains.

What Does Hydrogen Peroxide Do To The Rocks?

Honestly, what peroxide does to rocks depends on the concentration of the solution and the type of rock. In some cases, the answer is “nothing” or “not a dang thing.”

On the other hand, a high concentration of peroxide will react violently with asphalt, thus the answer is “a lot.”

Rockhounders often use peroxide to try and:

  • loosen or remove plant-type materials from the specimen (like moss or lichen)
  • loosen or remove other organics like clay, minerals
  • remove stains

Usually this is done by soaking the rocks for a period of minutes, hours, or days submerged in the solution.

I think in general, people would like to think of peroxide like an acid. You soak your rock and the peroxide would eat away at all the stuff you want to get rid of. After all, there’s a chemical reaction happening!

But this is seldom the case. What’s probably happening in most cases if the peroxide does seem to help is that the bubbles forming and foaming is helping dislodge tiny particles in the cracks of the mineral.

If you are looking to soak your rocks in something that will actually dissolve exterior formations like calcite, you’ll want to look towards acids.

Cleaning Rocks With Hydrogen Peroxide: How to Remove Stains

The easiest way to see whether hydrogen peroxide will do anything to clean up your rocks is to test it out:

  • Grab some of the rocks you’ve recently picked up
  • rinse them off with water
  • brush them off with a toothbrush to loosen any dirt or other particles
  • rinse again
  • dry
  • place the rocks in container (clear is best so you can see the rocks underneath if you are packing them in)
  • pour grocery store grade hydrogen peroxide into the container until the rocks are submerged
  • watch the foaming until you get bored or the foaming stops
  • give the rocks 2-3 days to sit in the solution, unless you see something happening in the bowl that looks alarming (like a growing chemical reaction, dark smoke, etc)
  • take the rocks out of the solution
  • rinse, scrub with a toothbrush, rinse again
  • dry

If the rocks look exactly the same, you can do one of two things. One, you can move on to other cleaning products to try and clean up the rocks some more. Two, you can try peroxide at a higher concentration.

If you are planning to use a higher concentration, we recommend that you slowly increase the concentration levels. 10%, then 20%, and so on. Over time, you’ll get an idea of what works and what doesn’t. And maybe what you’ll find out is that a lower concentration does work well enough for your purposes.

Alternatives to Hydrogen Peroxide

In addition to hydrogen peroxide, rockhounders use these other products to clean up rocks they’ve collected:

  • Beekeeper’s Friend
  • Toilet Cleaner
  • Lime Away
  • Vinegar
  • Soda water

If I have a really special piece, I won’t test a new cleaning solution on it. Instead, I’ll test it on other rocks, maybe even ones that I found on the same trip, made up of the same elements, around the same size, and see what happens.

Tips For Using Hydrogen Peroxide To Clean Rocks

Make Sure You Have The Material You Think You Do

Some stones are pretty easy going around chemicals (like quartz) while others dissolve when you put them in pretty benign solutions (like calcite with vinegar). Be sure that you know what stone you have so that you don’t accidentally cause a reaction.

Make Sure You Have The Right Product

When confronted with all of the various chemical names, hydrogen peroxide (H2O2) can be confused with hydrochloric acid (HCl). Not because the products are similar, but instead because people are not familiar with the names and make the assumption that one is the other (and vice versa).

If you plan to use peroxide, just confirm that you have what you need, and haven’t grabbed something else off the shelf that also starts with hydro- or hyper-.

Take Care When Using Higher Concentrations

For folks who are new to the business of cleaning up, tumbling, and polishing rocks and other specimens using chemical products, it is pretty easy to grab that grocery store grade of hydrogen peroxide out of the bathroom cabinet to try and get the job done.

You can get peroxide at the grocery store at a fairly low concentration in the first aid aisle for a few dollars. In this form, it is pretty innocuous. People use it to clean wounds, gargle, and clean their teeth.

But if you decide to employ higher concentrations (30% and such), treat it like it is a dangerous chemical. Wear protective goggles and gloves, and keep it off your skin.

Do Your Research Before You Make Mixtures

Do not mix cleaning products or chemicals without doing your research in advance. You could easily create something volatile or extremely harmful without even realizing what you have done.

Make sure you understand how much peroxide you actually need to add when you are making something that is 50-50 peroxide and something else (like vinegar). Confirm if the recipe means 2 cups of 3% concentration peroxide, for example.

The Bubbles Are Usually Oxygen and Water

Not always, but in general, when you use peroxide, it reacts to generate oxygen and water. Just because you see bubbles foaming up, it doesn’t mean that anything useful or helpful is happening.

Peroxide Can Get Old

Hydrogen Peroxide has a shelf life, like food. It looses effectiveness over time, especially after the bottle has been opened. Before you use it, try putting a few drops in the sink to see what happens. If you don’t see any bubbles, then it probably won’t do anything for you and your rocks.

How To Dispose of Peroxide After Using It To Clean Rocks?

When you are disposing of 3% peroxide, you could simply pour it down any drain in your house. I really don’t like putting anything down my house drains that has been used to clean rocks. Instead, I will usually walk outside with the mixture and pour it on weeds in my gravel driveway.

If you are using peroxide at a higher concentration, you cannot just pour the leftover solution down the drain without diluting it with water, or decomposing it with other substances.

More questions about cleaning up rocks? Check out our Rockhounding Knowledge Vault.