How to Clean Out a Fire Pit with Lava Rocks (6 Simple Steps)

How to Clean Out a Fire Pit with Lava Rocks

Last summer we bought ourselves a new outdoor table set with a built-in fire pit. We certainly got our money’s worth over the summer, but then I had to clean it. I quickly developed a method for cleaning out a fire pit with lava rocks and I’d like to share with you today. I feel it’s neat and works very well. 

Cleaning out a fire pit with lava rocks

Cleaning out a fire pit with lava rocks needn’t be as difficult as you think. Once the fire pit has cooled down, you remove all the ashes and dispose of them in your regular garbage. 

Now of course, the advantage to using lava rocks for your fire pit is that they are lightweight and porous, making it easier to get rid of any ash or cinders from a wood or charcoal-fired fire without having the mess clog up your drains. 

Based on that, here’s how you do it.

What you will need

1. Let the lava rocks cool down

Cover the fire pit after your last use and let the rocks cool. This will take between 20 minutes and one house before they have completely cooled so don’t touch them until 60 minutes after use. 

2. Soak and scrub the lava rocks clean

Wait until the lava rocks are cool enough that you can touch them without burning yourself. Then fill up a bucket with water and dish detergent and soak all the rocks thoroughly. 

You can use fine steel wool pads to scrub off any sooty residues along with burnt food particles on the outside portion of your lava rock. You may need to resoak several times or use another type of cleaner to get the best results.

I have found that the best natural cleaner is baking soda, bought in powder form at your local supermarket. Baking soda will not harm the rocks or any other part of your fire pit if it comes into contact with it during cleaning.

3. Rinse and dry the lava rocks 

Now use a hose to rinse off all your lava rocks thoroughly. This will let you to see if there are any remaining soot particles on the surface of the rocks or within cracks or fissures. You can also wash them with warm, sudsy water in your bathtub or use an outdoor shower for this purpose. 

You should let the lava rocks dry out completely before using them again for another fire pit session. Be sure to seal them with cooking oil if they are not naturally water-resistant. 

This will help keep air from penetrating the porous material of the rock, which helps maintain its original coloration and prevents rusting or rotting around the edges.

4. Prune any burns if wanted from the lava rocks

You can even prune any burnt edges of the lava rocks. Some find the scorch marks unsightly, and don’t like the sharp edges. Additionally, pruning off these rough surfaces will help expose any hidden soot particles that you might not be able to see at first glance.

I think that the best pruning tool for this would be a pair of metal cutting snips, which can be purchased at any hardware store.

#5. Address cracks and fissures

Use sandpaper to smooth out any rough edges you find. Then use paint to fill in any cracks or fissures found on the lava rocks until they are smooth to the touch. 

This step is optional, but it will help reduce any ash build-up around the edges of your rocks.

#6. Use a vacuum to clean out the fire pit

You can now clean out the fire pit itself. I use a vacuum cleaner on gentle mode to suck out all the ashes from any nooks and crannies. You may need to do this several times until you get all the debris removed. 


How to arrange lava rocks in a fire pit?

I’ve previously written an extensive guide on how to creatively arrange lava rocks on your fire pit.

Do lava rocks need to be cleaned?

Yes, lava rocks should be cleaned when used in an outdoor rock fire pit. Leaving soot and debris on the rocks for too long can erode the porous material and cause cracks. This will make your lava rocks weaker and more likely to break over time.

How long do lava rocks last in a fire pit?

Each type of lava rock has different physical properties and will last at various lengths in a fire pit. Generally, most lava rocks will last for a couple of years in a fire pit though. 

You can buy more on websites such as Amazon.


I know it’s a pain, but it’s worth cleaning your fire pit’s lave rocks at least once a summer, otherwise they will degrade and you need to buy a new pack.

You might also like…

Image in header via

Categorized as Backyard