Here is how to clean fire glass in a gas fire pit: turn the gas off, let the pit cool completely, scoop the glass into a bucket or old colander, rinse it with water until the soot and dust are gone, then let every piece dry fully before it goes back over the burner. Lava rock gets the same rinse but a longer dry, because it is porous. If the glass turns black again within a few fires, the problem is the flame, not the media.
Why fire glass gets dirty
Fire glass itself does not burn. MSI’s fire glass specification and care sheet gives a heat rating of 1,300 degrees Fahrenheit and says the glass does not emit smoke, ash or soot. The grime comes from elsewhere:
- Soot. Starfire Direct’s fire glass cleaning guide says the black film is soot, most visible on clear and white glass, and does not mean the glass is burnt. A lazy, yellow flame makes far more of it.
- Dust and debris. Leaves and blown dirt settle between pieces. MSI says to remove debris before lighting.
- Water. Rain leaves spots and mud, and wet media is a safety issue.
- Food and drinks. Spills leave a sticky film plain water may not lift.
How to clean fire glass step by step
You need gloves, safety glasses, a plastic scoop, a bucket, an old colander, a hose and a towel or tarp. Empava’s fire glass use and care guide and American Fire Products’ fire glass care instructions both warn the glass can be sharp and recommend gloves and safety glasses.
- Shut it down. Turn the fire pit valve off and close the tank or gas supply valve. Wait until the glass and pan are cool to the touch.
- Scoop the glass out. Starfire recommends small batches so you reach the dust between pieces. Use a colander you will never use for food again.
- Rinse. Run water through the glass and stir until the water runs clear. Starfire says soot rinses off with water; MSI and American Fire Products say a sprinkle of water handles routine dust.
- Mild soap only for sticky grime. For food or drink film, a few drops of mild dish soap in a bucket of water will loosen it. Rinse until no suds remain.
- Dry completely. Spread the glass on a towel or tarp. Empava says to allow a few hours; Starfire stresses no water should remain before it goes back in.
- Clean the pan, then reload to the depth your burner manual calls for.
Short on time? Starfire suggests swapping the top and bottom layers to hide surface dust.
Fire glass soot: when it means a gas or air mix problem
A light film after a season is normal. Heavy black soot that returns after a few burns means the burner is short of air. Our gas fire pit troubleshooting guide covers the usual causes: a blocked air intake or spider guard on propane, or an orifice that does not match the fuel. Clearing a blocked intake is an owner task. Changing an orifice, adding an air mixer or adjusting gas pressure is a job for a licensed gas fitter, following local code and the burner manual.
How to clean lava rock and dry it fully
Lava rock cleans the same way: cool pit, gas off, scoop into a bucket or colander, rinse with clean water until the runoff is clear. The difference is drying. Lava rock is porous and holds water, so give it longer than glass, spread out on a tarp.
Firegear Outdoors’ Pro Series H-burner manual warns that all media, lava rock and glass alike, can crack or pop when trapped moisture heats quickly. After heavy rain or humidity, it advises lighting the fire, stepping away and monitoring from a distance for no less than 30 minutes, until popping stops. For depth, mixing and more on popping, see our lava rock vs fire glass guide.
The same manual says to place lava rock by hand rather than pouring it from the bag, so dust does not plug the burner injectors or the pan’s weep holes. That applies after a cleaning, too.
Clean the burner and pan while the media is out
- Brush out the pan. Sweep up grit, leaves and broken glass. Starfire recommends wrapping glass fragments in a box or taped newspaper before disposal.
- Clear the drain holes. The HPC Fire rectangle drop-in Torpedo H-burner kit, 36 x 14 inch pan, propane ($623.20) uses pan weep holes and a raised burner hub to keep water out of the gas line. Both only work if the holes are open.
- Clear the ports. Firegear says to blow dust out of injectors with canned or compressed air while wearing safety glasses.
- Look for nests and damage. Firegear says not to use the appliance if any part has been under water; call a qualified service technician.
- Book the annual check. Firegear recommends inspection and cleaning at least yearly by a qualified service person.
When to replace vs reuse fire glass
Sooty or dusty glass is not damaged and can be reused for years. Replace or top up when:
- Pieces have chipped into small, sharp fragments.
- Color has faded. Empava’s warranty excludes the natural breakdown of colors over time, and American Fire Products recommends sun covers for long term sun exposure.
- The burner is no longer covered to the depth your manual calls for.
For a refill, the Empava 1/2 inch Shimmer Gold tempered fire glass, 10 lb is $54.79. For lava rock, the HPC Fire small black lava rock, 1/4 to 1/2 inch, 10 lb is $20.00 and the Prism Hardscapes 3/4 inch black lava rock, 27 lb is $16.00. Replace rock that has crumbled into grit, and check your manual for a minimum size: Firegear’s Pro H-burner calls for lava rock at least 1 inch across.
Use a cover to keep media clean
Starfire, American Fire Products and Firegear all recommend covering the fire feature between uses. Let the pit cool completely first.
- The HPC Fire vinyl fire pit cover, 45 inch round ($125.40) is black vinyl with an elastic band and a 3 year limited warranty.
- The HPC Fire stainless steel rectangle fire pit cover, 36 inch ($525.35) is a 40 x 18 x 1 inch hard lid for rectangle burners up to 36 inches.
Our fire pit cover guide covers sizing and vinyl vs metal.
Cleaning methods by media type
| Media | Routine care | Deep clean | Drying before relighting |
|---|---|---|---|
| Fire glass | Sprinkle with water; clear debris | Rinse in bucket or colander; mild soap for sticky film | Fully dry; a few hours per Empava |
| Clear or white fire glass | Same as fire glass | Same; soot shows most on these colors, per Starfire | Fully dry |
| Lava rock | Brush off leaves; keep covered | Rinse until water runs clear | Longer than glass; watch the first burn from a distance |
| Burner and pan | Keep weep holes clear | Brush out pan; compressed air in ports | Pan dry before media goes back |
Frequently asked questions
How do you get fire glass soot off?
Rinse the glass in a bucket or colander, stirring until the water runs clear, then dry it fully. If heavy soot keeps returning, have the burner’s air supply and orifice checked.
Can you reuse fire glass after cleaning?
Yes. Soot and dust do not damage it. Reuse it once completely dry, replacing only chipped fragments, faded glass, or what you need to restore the required depth.
How often should I clean fire glass and lava rock?
Clear debris before each use and rinse the media when it looks dull or sooty. Covering the pit between uses stretches the interval.
Is it safe to light a fire pit with wet lava rock?
Wet media can crack or pop. Dry it fully after cleaning. After rain, Firegear advises lighting it, stepping back and monitoring for at least 30 minutes until popping stops.
For help choosing a pit, burner and media, start with our fire pit buying guide or browse HPC Fire burners, covers and media. Questions about which media or cover fits your burner? Call us at 866-777-2590, Mon to Fri 9AM to 6PM PST. We offer free freight shipping on orders of $999 or more, with a $200 flat rate below that. Please read our return and refund policy before you order.
