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How to clean any grinder - and save the kief!

How to clean any grinder – and save the kief!

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The grinder is the unsung hero of the smoking process. 

In order to pack a bowl, roll a joint, or smoke a blunt, you need evenly crushed cannabis. Sure, you could crumble the weed with your fingers, grind it up with a mortar and pestle, or just use a bag of shake. You can make do without one in a pinch, but as any seasoned smoker will tell you, a good grinder makes a world of difference.

However, cannabis is a sticky plant (just try crumbling it with your fingers) and repeated use can clog a grinder up. Regular cleaning keeps your grinder turning smoothly. 

How often do you need to clean your grinder?

How often you need to clean your grinder entirely depends on how often you use it. The more you use it, the faster resin builds up and clogs the gears. When you’re fighting with your grinder to twist or open, it’s time to clean it. 

Grinders are typically made from metal or plastic and come in two designs. There are two-part grinders with a single chamber and teeth on either side and multi-chambered grinders with holes to separate the cannabis and kief.

Metal grinders

  • Usually made from zinc, aluminum, or stainless steel
  • Can last for years with regular maintenance 
  • Should be cleaned at least every 1 – 2 months 

These are typically multi-chambered grinders that are more expensive than plastic. But what you trade in upfront costs you get back in reliability and long-term use. A well-maintained metal grinder can last for years and provide you with plenty of kief. To clean a metal grinder, you need isopropyl alcohol.


  • Small, soft-bristled brush (a new or old toothbrush works) 
  • A plate or bowl 
  • Towel
  • Isopropyl alcohol
  • Ziplock bag

How to clean a metal grinder: 

  • Disassemble the grinder and dump any plant material onto a plate.
  • Place the grinder pieces in a zip bag with isopropyl alcohol. Let soak for 20 – 30 minutes, gently shaking the bag a few times. 
  • Remove the grinder from the bag and set aside. Using a small brush, vigorously scrub every part of the grinder. If you notice there are still sections where residue is built up, soak the section for another 10 minutes and brush again. 
  • Once you’ve scrubbed to your satisfaction, rinse the grinder under hot water, ensuring all the alcohol residue is gone. 
  • Towel your grinder dry or let it sit out for a few hours to dry completely. 

Plastic grinders 

  • Typically made from acrylic 
  • Plant residue can quickly build up on the sides
  • Should be cleaned at least monthly 

Plastic is an inexpensive grinder option and typically comes with one chamber, but some have an additional section for cannabis storage as well. Solvents or alcohol-based cleaning solutions can weaken or damage a plastic grinder over time, so you need dish soap to clean these. 


  • Small, soft-bristled brush (a new toothbrush works well) 
  • A plate or bowl 
  • Towel
  • Dish with warm water
  • Dish soap 

How to clean a plastic grinder: 

  • Disassemble the grinder and dump any plant material onto a plate. 
  • Soak the grinder in warm water for 10 minutes.
  • Add dish soap to your brush and scrub each part individually.
  • Rinse the grinder under warm water until the soap residue is gone. Towel dry or let sit until dry. 

Electric grinders 

  • Made from plastic and metal 
  • Should be cleaned after use


  • Small, soft-bristled brush (a new toothbrush works well) 
  • A plate or bowl
  • 2 tbsp rice 

How to clean an electric grinder: 

  • Unplug your grinder and take it apart. Use a small brush to clean the blades and sides. Save any plant material on a plate. 
  • Assemble your grinder and add 2 tbsp of rice. Grind the rice until it is the same consistency as flour. The dry rice particles will dry with the sticky trichomes. You can discard this, or use it as rice flour. 
  • Use a damp cloth to wipe the grinder clean and allow to dry. 

How to clean a grinder and save the kief

The best way to clean your weed grinder depends on what it’s made of. But first, consider saving kief before you clean it. 

If you just want to quickly clean your grinder, you can skip to the best way to clean a metal, plastic, or electric grinder. 

But you may want to save it! That sticky stuff causing your pieces to stick together are the trichomes from the plant, where a majority of the cannabinoids and terpenes are stored. Saving your kief before cleaning your grinder can give you extra potent kief or resin to add to your next bowl pack. 

Saving the kief

This method works for plastic and metal grinders. Do not freeze electric grinders.

  • Stage 1
    • disassemble the grinder and dump all of the plant material onto a plate or bowl. 
    • with a soft brush, lightly brush each part of the grinder, paying special attention to the teeth. If you have a pollen screen, take care to not warp it. 
    • tap the kief onto a plate or rolling tray. 
    • if the kief is too sticky to brush, proceed to stage 2. 
  • Stage 2
    • place each piece of the grinder upright in the freeze and leave for 30 minutes or until you’re ready to clean it. 
    • remove the grinder from the freezer. Immediately knock each part of the grinder against a hard flat surface to dislodge the kief.
    • Using a toothpick or small brush, gently scrape any remaining built-up plant material onto the plate. 

Extract the trichomes immediately after bringing your grinder out of the freezer. Don’t let it sit out; trichomes can quickly warm up and become sticky again.

Alternative ways to clean your grinder 

You can boil metal grinders to remove built-up residue. Boil the disassembled grinder in a pot of hot water for 5-10 minutes. Take the grinder pieces out and clean with a brush, paper towel, toothpick or q-tip. 

You can also simmer a metal grinder to make THC milk. While simmering metal in milk may not be your first choice for using the caked-on kief, a quick Google search shows dozens of results for the infamous “THC milk with grinder” recipe. This method works best for grinders that are gunked up from resin. The older the resin, the better, so the THCA has had time to oxidize to THC. 

If you’re willing to try anything once, here’s how you make it. 

  • Bring a pot of milk with the grinder pieces in it to a simmer. Don’t let it boil, as milk can evaporate off quickly. 
  • Simmer for 20 minutes. 
  • Remove the grinder pieces and scrub with dish soap under hot water. 
  • Strain the milk through a cheesecloth into a storage container and place in the fridge. 

You can use this milk as is or combine it in recipes as an ingredient. 

What can you do with kief? 

Kief is made from the trichomes that fall of the plant during grinding. These shiny, sticky compounds house most of the good stuff in cannabis- the cannabinoids and terpenes, making a small amount quite potent. You can use kief in a smoking session, press it into hash, or use it in your next edibles recipe. 

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