To clean a glass bong, shake it with isopropyl alcohol (91% or stronger) and coarse salt, let it soak about 30 minutes, then rinse with warm water until you can't smell alcohol. The alcohol dissolves the resin and the salt scrubs it off.
Change the water every session and do a full clean about once a week if you use it often. Keep the alcohol away from flames, work near an open window, and use soapy water instead on silicone.
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What you need
- Isopropyl alcohol, 91% or 99%. Pharmacies sell it as rubbing alcohol. Check the label, because many bottles are only 70%.
- Coarse salt: kosher, sea or rock salt. Table salt is too fine to scrub well.
- Warm water, a sink, and a towel.
- Plugs: rubber stoppers or bong-cleaning caps. Plastic wrap and a rubber band work. If you use your palms, wash your hands after, because the alcohol dries and irritates skin.
- Optional: a zip bag for the bowl and downstem, a bottle brush, pipe cleaners.
The alcohol and salt method
- Empty the water and rinse the bong with warm (not boiling) water to flush loose ash.
- Take it apart. Pull the bowl and the downstem. They go in their own bag with alcohol and salt, because they hold the worst of the buildup.
- Pour in alcohol until the resin-coated parts of the chamber are covered.
- Add coarse salt, a few spoonfuls. It's the scrubber.
- Plug every opening and shake for a minute or two. Swirl so the salt scrapes the sides.
- Let it soak about 30 minutes for a dirty bong. Shake again.
- Pour it out and rinse with warm water, inside and out, until there's no alcohol smell. Rinse the bowl and downstem the same way.
- Dry it on a towel, mouth down, and refill with fresh water before the next use.
Stubborn spots: a bottle brush through the neck, pipe cleaners through the downstem, or a second soak.
How to clean a glass bong without alcohol, with household items
- Hot water and dish soap. Fill with hot tap water and a squirt of dish soap, let it sit, shake with coarse salt, rinse. Slower than alcohol but fine for a lightly used bong.
- White vinegar and baking soda. A few spoonfuls of baking soda in the chamber, then vinegar. It foams and gives off gas, so wait until the fizzing stops before you plug the bong. Then shake with salt, soak, and rinse well.
- 3% hydrogen peroxide. The kind sold at pharmacies. It bubbles on the gunk and works more slowly than alcohol. Same soak-and-salt routine.
- Commercial bong cleaners. Usually alcohol or solvent based with abrasive beads. Follow the label.
Use one cleaner at a time. Rinse with water before you switch, and never mix them. The state fact sheet below lists peroxides as not safe to mix with isopropyl alcohol.
About boiling water. Some guides say to boil a glass piece in a pot. Pouring boiling water into cold glass, or dropping cold glass into boiling water, can crack it. If you want to use heat, warm the glass gradually and never let it touch the bottom of the pot. Alcohol and salt is easier and safer for the glass.
How to clean a silicone bong (and acrylic)
Most cleaning guides say to skip isopropyl alcohol on a silicone bong, because it can wear the silicone over time. Use warm soapy water and a brush. Or freeze the silicone piece for a few hours so the resin goes brittle and flexes off, then wash. Don't freeze glass. Acrylic (plastic) bongs can take a quick alcohol clean, but it clouds them with repeated use. Skip the salt on acrylic, because it scratches. Use a soft brush and rinse fast.
How to clean a pipe, bowl and downstem
These clog first. Seal each in a zip bag with alcohol and a spoonful of salt, shake, soak with the bong, and run a pipe cleaner through the downstem. A toothpick clears the hole in the bowl. Rinse until odor-free. Glass pipes clean the same way: bag, alcohol, salt, shake, soak, rinse.
How often to clean a bong
- Water: every session. Never leave it sitting overnight.
- Full clean: about weekly if you use it daily, or as soon as you see a film on the water, brown resin in the neck, or a smell.
This isn't just about taste. Stale bong water grows bacteria and biofilm. A 2017 case report described a daily bong user with a serious Pseudomonas lung infection. The same germ grew from his lungs and from his bong, and his doctors blamed the dirty bong water. It's one case, but the fix is easy. Fresh water and a weekly clean cost almost nothing.
Safety with isopropyl alcohol
Rubbing alcohol is flammable and the fumes are real
New Jersey's health department fact sheet lists isopropyl alcohol as a flammable liquid and a dangerous fire hazard, and says inhaling it can irritate the nose and throat, with heavy exposure causing headache, dizziness and confusion. It also says the vapor is heavier than air and can travel to a flame some distance away. So: no lighters, candles or stove flames nearby, including while the bong is still wet with alcohol. Open a window. Rinse until the smell is gone before you use the bong again, so you aren't inhaling alcohol vapor. Don't drink it. If someone swallows it or feels sick from fumes, call Poison Control at 1-800-222-1222.
Words you'll hear
- Resin, reclaim: the brown tar that builds up. Reclaim is the same kind of leftover in a dab rig. Clean it out with the rest.
- ISO: isopropyl alcohol.
- Biofilm: the slimy layer that forms on standing water.
- Downstem, slide: the removable tube and bowl. See how to use a bong.
- Pipe cleaners: the fuzzy wires from a craft store. Perfect for downstems.
Common questions
What removes resin from a bong?
Isopropyl alcohol dissolves it and coarse salt scrubs it loose. Shake, soak about 30 minutes, rinse until there's no alcohol smell. Vinegar and baking soda, hot soapy water, or 3% hydrogen peroxide work more slowly. Use one at a time and never mix them.
Does dish soap clean a bong?
Yes, for light buildup. Hot water, a squirt of dish soap, coarse salt, shake and soak. It won't cut through thick old resin the way alcohol does, and it's the right choice for silicone.
How do you clean a bong without alcohol or vinegar?
Hot tap water, dish soap and coarse salt, with a bottle brush for the neck. Or 3% hydrogen peroxide with salt. A silicone bong can go in the freezer so the resin goes brittle, but don't freeze glass. Expect to repeat.
Can you boil a bong to clean it?
You can, but cold glass in boiling water, or boiling water poured into cold glass, can crack it. If you use heat, warm the glass slowly and keep it off the pot's bottom. Alcohol and salt is easier on the glass.
How often should you change bong water?
Every session. Standing water grows bacteria and biofilm. One published case report linked a serious lung infection in a daily user to germs from his bong. Full clean about weekly, or sooner if you see film or smell it.
Why does my bong water have a film on it?
That's biofilm, a layer of bacteria and resin on standing water. Dump it, do a full alcohol-and-salt clean, and change the water each session from now on.
Is it safe to clean a bong with rubbing alcohol?
Yes, with care. It's flammable and the fumes irritate the nose and throat, so no flames nearby, open a window, and rinse thoroughly before using the bong. Use soapy water on silicone instead. Poison Control is 1-800-222-1222 if someone swallows it.
We cite government health agencies and peer-reviewed research. Numbers in the text link to the source.
- Government New Jersey Department of Health: Hazardous Substance Fact Sheet, Isopropyl Alcohol
- Peer-reviewed Respirology Case Reports (2017): Marijuana bong Pseudomonas lung infection
- Weedmaps: How to clean a bong (alcohol and salt, silicone, acrylic, alternatives, frequency)
- Vice: How to clean your bong (flammability, rinse until odor-free)
