How To Use Pressurized Water To Clean Contamination from Bubble Hash

Viviane Schute        

Cannabis enthusiast and student of the art of solventless extraction


Even the best washes are susceptible to contaminants, tiny pieces of plant material that slip through the wash bags along with resin heads. While hash makers can force this green chlorophyll through most of the sieves with pressurized water, leaving only the trichomes in the bags for collection, this isn’t so easy when it comes down to the 45 and 25 micron bags. Water by itself often won’t push the contaminants through the minuscule pores in these bags. This leaves otherwise high-quality loose resin tainted with plant contaminants, giving it a greenish hue and dashing its purity and value. 

Pure loose resin, trichome heads that break free from their stalks during ice water extraction, range in color from cloudy clear to creamy golden. Trichomes don’t contain any chlorophyll, which is the source of the green pigmentation found throughout the rest of the cannabis plant. Therefore, any green you see in your hash is a sure sign of plant matter contamination. 

Trichomes that have a greenish tint might seem impossible to clean, especially after they’ve been sprayed with pressurized water to no avail. A high-pressure stream of water can usually clean trichomes that collect in the 120, 90, and 75 micron bags, stripping away the chlorophyll so it can run through the bag. 

Rinsing all trichomes thoroughly with a high pressure stream of water is key to getting the cleanest pull out of every bag. A high-pressure stream of water helps to strip away contaminants from the resin and force it though the bubble bag. This will reduce plant contaminants before collection with your stainless steel spoon. And don’t worry about losing resin through the sieve. If it slips through the bag, you’ll be able to collect it in the next one! 




The pore sizes of these larger micron bags, such as the 120, 90, and 75, allow contamination to slip through. If it doesn’t, the technique we’ll discuss here can still work. But once these plant contaminants reach the 45 and 25 micron bags, a strong stream of cold water by itself often isn’t enough. The pores in the wash bag are too small to allow the contaminants to pass through. 

So what’s to be done with the mass of nearly microscopic shards of plant contaminants, which in aggregate cast a green shadow over an otherwise high-grade pull of loose resin? Fortunately, there’s a technique to literally wipe it away. 

Although you can sometimes see the green contamination floating on the top of wet resin collected at the bottom of a sieving bag, picking out the contaminants is impossible. Forcing them through the 45 and 25-micron pores won’t work either. But using a combination of pressurized water, a clean cloth or sponge, and the wash bag itself, we can actually extract the green right out of the hash. 

So let’s take a look at this simple and quick way to clean up your hash. 

Tools for Cleaning Contaminated Resin with Pressurized Water

In addition to all the tools and supplies you normally use for ice water extraction, such as a set of high-quality bubble wash bags, there are a couple things that make cleaning hash with pressurized water much more efficient. 

Lint Free Wipe
Lab grade cleanroom wipes or cloths are ideal. Certain sponges work too, as do stainless steel spoons or very fine sieving screens. Select material that won’t shed fibers into your hash. Avoid paper towels, which are liable to release fibers. 


High Pressure Spray Nozzle with “Flat” Setting
Hopefully, you’re already working with a source of cold, clean, pressurized water to rinse your hash in the sieving bags. But rather than a standard round jet stream of water, a flat or “fan” pattern of pressurized water is better for this technique. 

The water spreads out in a fan-like fashion as it exits the nozzle, creating a flow that’s both precise and easy to work with. Although the water fans out, it maintains a flat plane. 

How To Clean Your Loose Resin with Pressurized Water 

The basic concept is to use pressurized water to spray the plant contamination onto the side wall of the wash bag, where we can wipe it out with a cloth or sponge. 

Cannabis trichomes are heavier than the plant matter contamination. Plant contaminants will remain suspended above the trichomes as they bounce onto the sidewalls of the bag, floating in a bubbly froth while the resin sinks back down to the bottom of the bag. 

The trick is to keep the contaminants floating above the fan of water while the resin drops back down into the sieving bag. This tends to work best in the 45 and 25 micron bags. 

1. Adjust the spray nozzle to the “flat” setting so the water will shoot out in a flat fan pattern.

2. Spray the inside of the wash bag, aiming the water toward the middle of the sieve in order to gather all the resin to the very bottom of the sieve. 

3. Once the resin is puddled together in a small area, adjust the direction of the water to hit the resin at a slight angle. Let the flat steam of water glaze across the top of the resin. Imagine you’re trying to skim the cream off the top of milk.The idea is to skim the contamination off the top of the resin, and direct it into the sidewall of the wash bag. 

4. The contamination should stick to the sidewall in a green froth, while the resin drops back down into the center of the bag. 

5. Use your cloth or sponge to wipe the contamination from the sidewall. Avoid collecting any resin with the contamination (although some loss is inevitable). 

6. Repeat this process until you’re no longer able to collect plant contaminants without also wiping away trichomes.  

Things To Avoid

The main thing to avoid is dabbing out too much hash along with the plant contamination. A bit of lost resin is inevitable with this technique, but the key is to minimize the amount that gets wiped away with the contamination. 

Also, stay away from cloths or wipes or sponges that may shed fibers into the hash. Paper towels are especially liable to do so. 

As always, maintain ice cold temperatures for cleaning contamination using pressurized water. Any water that comes into contact with the resin should be as cold as possible. Avoid using water that’s above 40 degrees Fahrenheit. 



Finding tiny pieces of plant contamination in your 25 and 45 micron bags is common, especially after you’ve already run the material a couple of times. Seeing this contamination completely blended in with the resin makes separation and removal seem impossible. But fortunately, there is in fact a way to clean your hash and greatly reduce the amount of contamination.

Using ice cold, pressurized water and a clean, lint free cloth or sponge is an easy way to clean plant contamination from loose resin. A flat stream of water sprayed over loose resin that’s gathered at the bottom of a 25 or 45 micron bubble wash bag can effectively skim the tiny plant particles right off the top. This green froth can be guided away from the rest of the resin with the stream of water, as the plant contaminants tend to stay suspended in a bubbly mass. Most of the resin sinks back down, making it easy to wipe the contamination away from the side of the bag. 

Have you ever tried this method of cleaning loose resin? Let us know in the comments!

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What is plant contamination in loose resin?
Tiny pieces of plant material, which show up as green specks, are considered contamination within loose resin.

How does hash get contaminated?
Cannabis material breaks apart and releases tiny shards and splinters of plant matter during ice water extraction, which can end up in the hash.

Why doesn’t contamination rinse out of hash in 25 and 45 micron bubble bags?
The tiny pores in 25 and 45 micron bags are so small that they often don’t allow plant contamination to pass through.

What kind of wipes should you use for cleaning loose resin with pressurized water?
Only use wipes or cloths that don’t release fibers to clean loose resin with pressurized water.

What setting should you use on your spray nozzle to clean hash with pressurized water?
The flat setting on the spray nozzle is the best for spraying water in order to clean plant contamination out of the 25 and 45 micron bubble wash bags. 


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