How to Clean a Grinder: The 4 Best Ways + A Surprisingly Tasty Trick

Keeping your weed grinder clean is the secret to a smooth, efficient grind. This may be common knowledge to you, but as a newbie to grinding flower, I didn’t know that resin and plant residue can accumulate over time, leading to sticky, clogged parts that impact performance. Cleaning your grinder consistently ensures that you get the best consistency and flavor from your herb and prolongs the life of your accessory.

I asked our flower-loving editors to share their favorite ways to clean a grinder. Here’s what they had to say. 

How Often Should You Clean Your Grinder?

You should not clean your grinder after every use, however, regular cleaning of your grinder is important.

Your grinder cleaning schedule depends on how often you use it. If you’re a daily user, clean it every few weeks. For occasional users, a monthly or seasonal cleaning should suffice. 

If you notice your grinder is becoming sticky, hard to turn, or not grinding as efficiently, these are signs that it needs a good cleaning.

How to Clean Your Weed Grinder

The first step to cleaning a grinder is to disassemble it. Once you have taken it apart, try the methods below to remove the build-up. If your grinder is very resinated, you may need to use a combination of methods.

After cleaning your grinder, pat it dry, then allow it to air dry completely before reassembling it. The last thing you want is mold in your grinder! You can use a DIY grinder hack while you wait for it to dry.

How to Clean a Plastic Grinder

Many plastic grinders are robust as they’re designed to be travel-friendly, but you’ll want to use care when cleaning.

Plastic grinders shouldn’t be exposed to extremely cold temperatures as this can cause cracking. They can be submerged in warm water, but be aware that plastics release toxins into liquid. Additionally, chemicals such as alcohol and acetone are corrosive to plastic, so it’s best to avoid methods that use them.

How to Clean a Metal Grinder

There are many ways to clean a metal grinder. One common method is to freeze it, scrape away the residue, then soak it in isopropyl alcohol and rinse it to remove any remaining build-up.

Preserving Kief While Cleaning Your Grinder

The plant matter that builds up in your grinder can be saved for consumption. In fact, the trichome crystals (kief) are what you might call a cannabis delicacy.

Some grinders come with screens that collect the kief that falls off the flower while grinding — aka kief catchers. If your grinder has a kief catcher, scrape the screen to collect the kief as part of your cleaning process. Sprinkle it over flower or decarboxylate it for your next batch of canna oil.

Kief can also get stuck to the teeth and other parts of the grinder. You can capture this magic plant dust with most of these cleaning methods.

Disassembly and Brushing 

Brushing is a simple cleaning method that doesn’t require any special equipment. It’s also the recommended cleaning procedure for most wooden and electric grinders. 

• Use a soft brush: Use a soft brush such as a toothbrush or small paintbrush to sweep residue from the teeth and other parts. A cotton swab can also be handy for cleaning between the teeth.
• Collect the kief: Work over a plate or piece of paper if you want to collect the kief.
• Rinse and dry (if applicable): If the grinder is metal or plastic, rinse the parts in warm water. If you do rinse the grinder, be sure to let it air dry entirely.

If your grinder is very dirty, try freezing it before you brush it clean.

Freezing Method 

Putting a grinder in the freezer causes the sticky plant residue to harden and become brittle. This makes it easy to scrape out the resin and kief. 

• Freeze the grinder: Place the grinder parts in the freezer for 30-60 minutes. 
• Tap and scrape: After freezing, tap the grinder pieces over a paper towel to dislodge loose particles. Use a toothpick or brush to scrape off any remaining debris. 
• Collect the kief: This is your chance to rescue the kief! Gather up everything you scraped out.

Freezing and scraping may be enough, but many people swear that following it up with an isopropyl alcohol bath is the best way to clean a grinder.

Isopropyl Alcohol Soak 

If you want your metal grinder to gleam like it did the day you took it out of the box, an isopropyl alcohol soak is your best bet. Here’s how to deep clean a grinder with this method:

• Soak in isopropyl alcohol: Place the pieces in a container filled with isopropyl alcohol (90% or higher) and soak for 20-30 minutes. A high-proof spirit such as vodka also works. 
• Scrub and rinse: Use a brush to scrub away any remaining residue, then rinse with warm water.
• Filter out the kief (optional): To get every bit of kief, save the alcohol you used to clean the grinder and pour it through a coffee filter. Allow the kief to dry completely, then carefully use a sharp flat-edged object such as a razor or kief scraper to break it up and transfer it to a container (or enjoy immediately).

Don’t forget to dry your grinder before putting it back together.

Isopropyl alcohol is powerful, but if any residue remains, you can spot-clean it with acetone (nail polish remover) and a cotton swab or cotton pad. Be sure to rinse it well after using acetone.

Vinegar and Salt Method

If you don’t have any isopropyl alcohol or you don’t want to use it on your plastic grinder, the salt and vinegar approach is a great alternative. 

• Prepare the cleaning solution: Mix equal parts white vinegar and water in a container. Add a tablespoon of coarse salt (like kosher salt or sea salt) to the solution.
• Soak the grinder: Submerge the grinder parts in the vinegar and salt solution. Let them soak for 30 minutes to an hour.
• Scrub and rinse: Use a brush to scrub off any remaining residue. The coarse salt acts as a natural abrasive, helping to remove stubborn particles. Rinse the parts thoroughly with warm water.

Make sure your grinder is dry before reassembling. 

Clean a Grinder With Milk for a Sweet Reward

If you haven’t tried canna milk (aka cannabis milk), you’re in for a treat — and you can enjoy it right after you clean your grinder. As you might have guessed, canna milk is milk infused with cannabis. You can make it with flower, but why not use the kief that’s already in your grinder? 

Your grinder and milk have a symbiotic relationship. While the cannabinoids in the kief infuse into the milk, the fats and proteins in the milk help break down the resin and other residues. This method is particularly effective for cleaning sticky grinders. 

You can technically use any milk or milk alternative when making canna milk, but whole milk is typically recommended for cleaning a grinder because it contains the fats and proteins needed to dissolve the plant matter. If you’re looking for a plant-based option, use something with fat such as coconut milk.

Note: Because chemicals from plastic can leach into the milk, this method should not be used for plastic grinders.

How to Boil a Grinder in Milk

To clean your grinder with milk leave a it in milk for several minutes to make a milky infusion you can drink or use in recipes. (Infused ice cream, anyone?)

• Boil the milk: Bring a pot of milk to a simmer. Make sure there’s enough milk to completely submerge the grinder parts. 
• Soak the grinder: Place the grinder parts into the boiling milk. Let them simmer for at least 15 minutes and up to one hour.
• Remove and scrub: Carefully remove the grinder parts from the milk (use tongs or a slotted spoon to avoid burns). Allow them to cool, then rinse with warm water and scrub with a brush to remove any remaining residue. Dry thoroughly.

Let the milk cool before transferring it to a storage container. Refrigerate until ready to use.

Grinder Cleaning FAQs

Can I Boil My Grinder in Milk?

Yes, so long as you don’t have a wooden or plastic grinder, you can boil it in milk to clean it and infuse the milk with THC and other cannabinoids. 

Can Mold Grow in a Weed Grinder?

Yes, mold can grow in a weed grinder if it is not cleaned regularly and if it remains in a damp environment.

How to Dry a Grinder After Cleaning It

After cleaning, dry your grinder by patting it with a towel and leaving it in a dry, airy place to ensure all moisture evaporates.

Can I Use Hydrogen Peroxide to Clean My Grinder?

Yes, hydrogen peroxide can be used to clean a grinder instead of isopropyl alcohol or vinegar. Soak it for several minutes and then scrub away any residue.

Can Acetone Clean a Grinder?

Yes, acetone can clean a grinder effectively by dissolving residues, but it must be thoroughly rinsed off afterward to ensure no harmful chemicals remain.

Can You Use Vodka to Clean Your Grinder?

Yes, vodka can be used to clean a grinder as its alcohol content helps dissolve residues.

How to Clean Grinder Without Isopropyl Alcohol

You can clean a grinder without isopropyl alcohol using alternatives like hydrogen peroxide, vinegar, or boiling it in milk.

Can You Boil a Metal Grinder to Clean It?

Yes, boiling a metal grinder in milk or water can help loosen and remove residue. Just make sure all of the components can withstand heat and dry it thoroughly afterward.

Can You Put a Weed Grinder in the Dishwasher?

Putting a weed grinder in the dishwasher is not recommended because the heat and detergent may damage it or leave residues. 

What Happens if You Don’t Clean Your Weed Grinder?

If you don't clean your weed grinder, it can become clogged, less efficient, and may even develop mold or bacteria.