How to Clean Your Grinder (And Save Kief)

If your grinder is getting hard to turn its probably because sticky resin and leftover plant material build up over time, making a quick grind feel like a workout.

Here’s how to clean your grinder, get it turning smoothly again, and safely save your kief (the fine, powdery trichomes collected in your grinder).

Cleaning Your Grinder – Why Is It Important?

While a grinder may technically remain functional even when completely coated in cannabis oil and gunked up beyond recognition, such neglect creates several distinct problems:

• Grind consistency is affected: Gunky and dull teeth end up tearing the flower instead of making a clean cut. As a result, you have uneven pieces that burn unevenly.

• It blocks your kief screen: The fine mesh screen in a multi-piece model easily gets clogged with oils and micro-particles. If those pores are blocked, your bottom chamber stops collecting.

• It strains your hands: The added friction on the outer rims and threads causes twisting to be exhausting.

• It introduces stale debris: Old, oxidized plant material sits in the corners and mixes with your fresh flower, ruining the flavor profile of your strain.

What You Will Need

You’ll need a few things to clean your weed grinder:

• Isopropyl Alcohol (91% or higher) to break down stubborn plant resin almost instantly.

• A Sturdy-Bristle Brush (an old toothbrush will suffice), or alternatively, a soft bristle brush or small paintbrush, if that’s your vibe.

• A freezer

• A Toothpick or Some Other Scraper, such as cotton swabs, pollen scrapers, or even guitar picks for getting deep inside the nooks and crannies.

• A Glass Bowl or Ziploc Bag to submerge your disassembled pieces.

• A Clean Plate or Parchment Paper to catch all your reclaimed material.

• Microfiber Towel or Paper Towels for drying.

A Quick Safety Note on Plastic vs. Metal Grinders

Remember how I mentioned alcohol earlier? Well, isopropyl alcohol cannot be used with plastics or acrylic grinders whatsoever, as the high proof solution interacts poorly with acrylics and causes cracking, warping, fading and leaching of toxic synthetics directly into your next batch. Thus, soaking in alcohol should be exclusively reserved for metal/aluminum grinders.

How to Clean Metal and Aluminium Grinders

Step 1: Take Your Grinder Apart

Start by taking apart your grinder. Remove the top lid, teeth chamber, screen section, and bottom catch tray.

Step 2: Freeze the Grinder for 30 Minutes

Once everything is apart, it’s time for a little freezy magic. Place all the pieces onto a plate and pop them into the freezer for 20 to 30 minutes. Why freeze, you may wonder? Freezing cannabis resin makes it rigid and brittle, allowing you to scrape out those bits more easily

Note: Do not freeze electric grinders.

Step 3: Collect the Kief

After your grinder has spent some time in the freezer, take it out and act quickly to preserve the chill.

1. Tap your pieces: Put each piece above the parchment paper and gently tap it against your hand or some soft surface. You will be surprised how much frozen resin will fall off of your grinder.

2. Brush the screen: Use your toothbrush or a small paintbrush to gently brush the inner and outer sides of the mesh screen. Be careful not to press too hard and stretch the screen from its housing.

3. Clean the teeth and rims: Take your toothpick and clean out all the compressed kief that is pressed into the corners of the teeth and rims of the grinder.

Collect all of the dislodged golden powder on your parchment paper and store it in your kief catcher or a small glass jar.

Step 2: Soak the Pieces in Alcohol

Once you’ve gathered all that glorious golden powder, it’s time to give the rest of the pieces a deep cleaning to tackle the gunk. For this, place all the aluminum or steel pieces in a glass dish, or a heavy-duty Ziploc bag, and pour in enough isopropyl alcohol to cover them completely. Let them soak for 15 to 30 minutes. If your tools are particularly dirty, a longer soak of 45 minutes can do wonders.

Step 4: Scrub the Grinder

After soaking, wear some dishwashing gloves and scrub each piece with your toothbrush. Pay special attention to the gaps between the teeth and the edges. For any stubborn spots, a little direct scrubbing with alcohol can make all the difference.

Step 5: Rinse and Dry the Grinder

Once everything is nice and clean, rinse the parts under running tap water for at least a minute to wash away any remaining alcohol and debris. Let them air dry completely before reassembling. Now you can enjoy using your fresh, clean grinder!

Pro tip: For a smoother grind, lightly apply a small drop of food-grade hemp oil or vegetable glycerin to the threads, but skip any petroleum-based products, as they're toxic if inhaled and will ruin your flower!

How to Clean Wood, Acrylic & Plastic Grinders

If your grinder is made of either plastic, acrylic or natural wood, then forget about soaking it in the alcohol solution and use the more gentle and solvent-free way to clean it.

Reasons Why Not to Use Alcohol Solution on Plastic

Being a solvent, alcohol tends to dissolve plastic materials. Consequently, soaking your acrylic grinder in a high-proof isopropyl will cause numerous micro-fractures (crazing) in your clear plastic, making it cloudy and brittle. Eventually, those micro-cracks can flake off microscopic plastic pieces directly into your flower. Obviously, it is something that needs to be avoided.

The Warm Water and Dish Soap Method

For non-metallic tools, such as your plastic or acrylic grinder, warm temperature and grease-cleaning soap are the best options:

1. Warm water and dish soap preparation: Put some warm (but not hot!) water in a bowl and add a couple of drops of grease-cleaning liquid dish soap there.

2. Soak plastic/grinder: Put the plastic pieces into the water and leave them there for 10-15 minutes. (In case of wooden grinder, do not soak the wood itself in the water, but rather dip a cloth into the solution and scrub the surfaces by hand in order to prevent wood swelling).

3. Scrub hard: Scrub the soft parts of the teeth with the stiff-bristled toothbrush.

4. Rinse well: Wash away all soap suds under lukewarm running water before drying

What can you do with the reclaimed kief? 

You now have the knowledge of how to clean a grinder and get some kief in the process. You wonder what I can use this kief for. Here are several ideas of how you can use your kief alone or in combination with other marijuana products.

• Top off a bowl. Sprinkle a little kief over ground flower in your pipe or bong for an extra boost in potency.

• Roll an infused joint. Mix kief evenly into your ground flower before rolling to give your usual joint a stronger kick.

• Press it into hash. Compress collected kief into a compact piece of hash using pressure and gentle heat.

• Make moon rocks. Coat a cannabis bud with a sticky concentrate, then roll it in kief to create a potent, crystal-covered nug.

• Use it in edibles. Decarboxylate your kief first to activate its cannabinoids, then blend it into butter or oil for homemade treats.

Frequently Asked Questions

How often should I clean my grinder?

Clean weed grinder every 2 to 4 weeks if you use it regularly or every 2 months if you are a light user.

Can I boil my metal grinder in water to clean it?

Yes, it works well in dissolving the resin but I wouldn't advise doing it often. Mineral scale can get deposited on the threads when boiling in hard water while handling hot metal is dangerous. Isopropyl alcohol soak is way better and more efficient.

What percentage of isopropyl alcohol is best?

Use 91% or 99% isopropyl alcohol. 70% rubbing alcohol contains less alcohol and more water which makes it less effective in cleaning process since it needs more time for dissolving oils and evaporating from the surface.

Is the kief trapped inside a grinder safe to smoke?

You can smoke the reclaimed kief from a grinder as long as its not overly old or moldy.