Understanding Contamination in Scentwork

Because contamination in scentwork confuses the game.

If your dog keeps alerting where odour was, not where it is, then you’re not teaching odour discrimination - you’re teaching history.

At the early stages of training, you want the odour picture to be crystal clear:

“This odour, in this place, gets me my toy or treat. Simple.”

But if lingering odour ends up in the wrong place, your dog might start alerting on residual scent; molecules inadvertently transferred through your hands, gloves, or tools onto surfaces instead of the actual hide (like a tin, plastic container, or scent vessel).

That leads to false indications, where the dog is signalling to the handler what they believe is the source - but instead, they may be picking up on accidental contamination.

And here’s the important bit: the dog isn’t actually wrong.

They’re doing exactly what we’ve taught them to do - detect odour.

But what we want to build is the dog’s ability to locate source odour, not lingering or residual scent.

This can show up as:

• Dogs alerting on disposable gloves, human scent, or containers

• Confusion over what’s actually being rewarded

• Reinforcement of incorrect or inconsistent behaviour

For newer dogs, this can knock confidence.
For more experienced sniffers, it can introduce frustrating inaccuracies that are tricky to troubleshoot later.

That said, as your dog gains experience, you can start to introduce intentional distractions; like food, toys, human scent, or other non-target odours. This isn’t contamination; it’s a deliberate training strategy.

Used thoughtfully, these elements help test your dog’s commitment to target odour and build confidence in more complex environments.

Mixing up odours also encourages dogs to problem-solve more intricate scent pictures and helping them develop better discrimination skills when working around background odours.

In fact research has shown that dogs trained using varied odour mixtures are better at identifying a target scent, even when that scent is buried within a “noisy” environment full of other smells.

In summary, intentional distraction is part of the plan.

Unintentional contamination is what we want to avoid.

Contamination in scentwork is sneaky - and honestly, we’ve all been there!

It happens when:

• You touch odour, then touch a chair, table, or surface in the search area

• Your scent training box is placed in the search space, carrying possible leaks or residual odour

• Used hides accidentally end up in your pocket (oops!)

• Odour gets on your gloves… and then on everything else (yes, we’ve all done it)

• The search area was recently used for a strong odour; even food scents can distract or confuse

• There’s leftover odour from a previous search that hasn’t cleared fully, or given enough time to disperse.

Sometimes, the contamination is so subtle, only your dog will know it’s there.🐶
And when that happens… your sniffer goes rogue (but for all the right reasons).

 We know that odours behave differently depending on several factors..

To get a better understanding, let's get a bit “science-y” and break down the most common odours used in the UK..

Kong
Low vapour pressure, making it a cleaner odour-training tool. It stays close to the source, with minimal odour escape, That means the Red Kong scent doesn’t overwhelm the search area, great for building precise source finding skills. With its low propensitiy for residual odour, it makes the Kong a very forgiving odour to train with. Perfect odour for novice and experienced dogs alike!

Gun Oil (Napier Gun Oil)
Has mid-to-high vapour pressure - persistent and travels well. Excellent for targeting accuracy and large-area searches, but it spreads easily (including through your storage kit or gloves) and can lead to contamination if you’re not cautious

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Clove
High vapour pressure, fruity, spicy, and diffuses quickly. Ideal for training strong indications. But it can also flood a room with odour if not careful, this can be especially tricky for beginner dogs

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Truffle (English Truffle Oil - preferred brand)
Complex and earthy, often used via truffle oil. It offers layered scent profiles, but as an oil it’s prone to leakage and contamination, so watch how you prepare your soaks! The oil is strong and lingering.

Why does this matter?

Odours with low vapour pressure (like Kong) keep the scent localized, helping dogs learn precise source detection.

Odours with high or complex vapour pressure disperse more broadly, which can either help build motivation or overwhelm a novice dog.

Understanding odour characteristics helps you:

• Choose the right odour for your dog’s training level

• Prevent contamination by matching odour volatility to setting and skill level

• Troubleshoot false alerts caused by lingering odour residue

Whilst we can't sniff like a dog - if we have a better understanding of how odour behaves, we are already half way there in reducing contamination in scentwork.

 In fact just a few simple habits can make a big difference to your dog’s clarity and success in the search.

Top tips for keeping it clean:

• Dedicate specific tools for each odour

• Use one airtight storage box per odour (we like to double-box with a tin inside)

• Clearly label and separate your gear

• Use gloves or tweezers when handling odour - then store them separately after use

• Use one pair of gloves per search session , remove them cleanly, and dispose of them properly (don’t toss them back in your bag!)

• Keep storage containers and spare tins out of the search area

• Transfer used soaks back into sealed containers when not in use

Keeping your handling tools clean and separate helps your dog focus on the intended target odour, and not muddy the scent picture with accidential cross - contamination😶

Hope you enjoyed this article, do check out our blog section for more sniffy stuff!

Happy Sniffing!

Kate and The Sniffer Shop Team