If your grinder is hard to twist, squeaks, or leaves chunks instead of an even grind, it's not broken. It's dirty. Resin and fine dust build up on the teeth and in the threads over time. A good cleaning takes about an hour, most of it hands-off, and uses things you probably already have.

What you need

• Isopropyl alcohol, 91% or higher (for metal grinders)
• Coarse salt, like kosher or sea salt
• A zip-top bag, or a glass jar or container with a tight lid
• A soft brush or an old toothbrush, plus cotton swabs or toothpicks
• Warm water and a little dish soap
• A towel or paper towels

Want something made for the job? Our cleaning collection has resin cleaners that work faster than plain alcohol.

Step 1: Collect the kief

Before anything gets wet, save the kief, the fine powder that collects in the bottom chamber. Open the bottom chamber over a clean sheet of paper and scrape it out with the small scraper that came with your grinder, or a clean card. Tap the chamber and brush the screen from the top side to knock the rest loose. Alcohol and water ruin kief, so always do this first.

Optional: if the kief is caked on or the grinder is very sticky, put it in the freezer for 20 to 30 minutes first. Cold makes resin brittle, so the kief and buildup come off the metal more easily.

Step 2: Take it apart

Unscrew every piece. A four-piece grinder separates into the lid, the grinding chamber, the screen chamber and the kief catcher. Brush out any loose bits with a dry brush. Check for anything that shouldn't get wet, like a wood or plastic part or a sticker; those pieces get cleaned by hand in step 5.

Step 3: Soak it in alcohol and salt

This is where most of the cleaning happens. The alcohol dissolves the resin, and the salt works as a scrubber that knocks it loose as you shake. Salt doesn't dissolve in alcohol, so it keeps scrubbing the whole time. Pick whichever method is easier:

• In a jar or container: put the metal pieces in, pour in enough isopropyl alcohol to cover them completely and add a tablespoon or two of coarse salt. Close the lid tight and shake hard for a minute.
• In a zip-top bag: put the metal pieces in the bag, add a tablespoon or two of coarse salt and pour in enough alcohol to cover them. Squeeze out the air, seal it and shake and massage the bag for a minute so the salt gets into the teeth and threads.

Let it soak for 20 to 30 minutes, shaking again every 10 minutes. Very sticky grinders can soak longer. The alcohol turns cloudy and brown as the resin comes off.

Only soak metal grinders. Alcohol can cloud, crack or weaken plastic, and it dries out wood. If your grinder isn't metal, skip to the section on plastic and wood grinders below.

Step 4: Scrub the teeth and threads

Take each piece out. Most of the buildup should be gone. Scrub what's left with the brush, working around every tooth. Use a toothpick or cotton swab for the corners and the threads, where buildup makes the grinder hard to twist. Brush the screen gently from both sides so you don't stretch or tear it. Dip the brush back in the alcohol for stubborn spots.

Step 5: Rinse and dry completely

Rinse every piece under warm water with a drop of dish soap to wash away the alcohol, salt and loosened resin. Run water through the threads and the screen until no salt grains are left. Then dry each piece with a towel and let them air-dry for at least an hour, or until there's no alcohol smell left. Put it back together only when every piece is fully dry, especially the threads and screen.

How to clean a plastic or wood grinder

• Plastic: collect the kief and brush it out. If it's still sticky, wash it in warm soapy water with a toothbrush. Skip the alcohol soak.
• Wood: never soak it. Collect the kief, brush the teeth with a dry toothbrush and wipe the inside with a cloth just barely dampened with alcohol. Let it dry open.
• Hemp or plant-based plastic (like some Santa Cruz Shredder grinders): treat it like plastic, and check the maker's care instructions first.

How often should you clean a grinder?

For daily use, a quick dry brush every week and a full clean every month or so keeps it turning smoothly. Clean it sooner if it starts to stick, squeak, or grind unevenly. A grinder that's cared for lasts years. If yours has dull teeth or a torn screen, it's time for a new grinder.

FAQ

Can I put my grinder in the dishwasher?
We don't recommend it. Dishwasher heat and detergent can damage finishes and screens, and it won't break down resin as well as alcohol.

Why add salt?
Salt is a gentle scrubber. Shaken with the alcohol, it gets between the teeth and into the threads and knocks off resin that soaking alone would leave behind. Coarse salt works better than table salt.

Can I use rubbing alcohol that's 70%?
It works, but slower. The extra water in 70% alcohol doesn't dissolve resin as well, so plan on a longer soak and more scrubbing.

Will cleaning remove the kief?
Yes, so collect it first, while the grinder is still dry (step 1).

What's the best way to keep a grinder clean longer?
Grind herb that isn't too moist, brush it out after each session and keep it closed when you're not using it.

Once your grinder is clean, put it to work: here's our guide to filling pre-rolled cones. Shop all herb grinders and cleaning supplies at HIGHBOIS. Everything ships in plain packaging.