With more states legalizing medical and recreational marijuana, the quality of cannabis being sold is under more scrutiny than ever before. After all, not all growers have the same high-quality standards.

Considering you bring cannabis into your body’s digestive and respiratory systems, it is vital to have clean marijuana. There are several contaminants you should concern yourself with when it comes to your weed purchase. Pesticides are a big one, as are bacteria and yeasts that could be hiding in your bud. Mold is another potentially harmful contaminant because of the endotoxins and mycotoxins it releases. These toxins are harmful to everyone, but especially those with autoimmune conditions and respiratory conditions. For those using marijuana for medical purposes, this can be adding oxygen to the flames rather than smothering it.

So, how do you protect yourself from less scrupulous growers looking to get in on this growing market by cutting corners? How do you know if the weed you’re paying for is high quality or contains dangerous contaminants that you have to be wary of putting into your body? It’s all about educating yourself on the product by looking at it, touching it, and talking with your seller.

Inspecting Your Purchase

Perform a visual inspection of your cannabis purchase to look for any substances that don’t look right on the bud (you may want to look at it with a magnifying glass for a good, close view). Crystalline materials and other foreign substances caked on the bud or stem can be an indication of contaminants. It is also helpful to feel the bud or stalk for a physical inspection. When you feel a chalky or gritty texture, this may indicate that the plant it came from was sprayed.

You may also notice differences when you smoke your purchase. Smoke that has a chemical scent or seems particularly harsh can be a sign your weed purchase was contaminated and may require further examination. A bad taste can also be a sign that your pot is not up to snuff when it comes to contaminants.

(For tips on storing your purchase, check out Oven Bags for Storing Cannabis?! (They Work))

Talk to Your Seller

Sellers who are knowledgeable about their products are going to know pertinent information that can help make you feel better about the quality of the weed you’re buying. Ask them if the cannabis was grown organically. You may want to inquire if they offer eco-friendly or sun-grown cannabis. Also, ask them about their quality control process. Do they have their products tested for pesticide and other contaminants? Don’t forget to ask if your purchase has any certifications from third-party organizations like Clean Green, the Organic Cannabis Association, or Certified Kind. Conversely, avoid going to a cannabis seller that makes you feel uncomfortable and doesn’t want you to inspect your purchase. A seller that doesn’t know much about their product—how it was grown, what was used on it, etc.—should probably be avoided if possible as well.

No matter where you source your marijuana from, you have the right to be safe from contaminants. It may not be easy to identify them in your weed purchase, but it’s worth the effort. Take the time to inspect your purchase and don’t be shy when it comes to asking questions at the dispensary. Your seller should help you to feel comfortable with the quality of your purchase, and if they can’t, it may be time to find another.

(For more on the dangers of weed, check out Is There Any Danger of Pesticide Residues in Cannabis Concentrates?)