I’m a mom of one and don’t use or associate with any drug stuff. I recently bought a backpack off a buy and sell and after I got it home I noticed it smelled like cigarettes. So I went through all the pockets and found a small bag of what appeared to look like a small amount of residue of hard drugs. I called the police and they came and picked it up from me to dispose of it. But I couldn’t confirm what it was. And then I washed the backpack on hot.

I’m wondering if I can still travel with this backpack. I bought it specifically for my trip to carry it on and really want to use it. Someone warned me not to take it in case there was still a scent or residue in the bag. They felt I could get in a lot of trouble. Common sense tells me that I couldn’t possibly be kept from my flight or get in trouble since there wouldn’t be anything they’d find. But I wanted to ask if anyone knows for sure about this.

Is it likely that a scanner or swab or whatever those silver wand things are would pick up any trace of that stuff? And if so what would happen?

I’ve washed the bag. Is there anything else I can do to ensure it’s totally cleaned up?

  • 32
    The wands look for explosives. Dogs are used for drugs. Also, there are probably more drug residues on the bills in your wallet.
    – npl
    Jul 29, 2018 at 19:34
  • 5
    Related but not quite a duplicate: Airport security: what if I carry an item with traces of explosive? Jul 29, 2018 at 21:48
  • @npl Not true. They do swab bags for drugs. They stick it in this machine and if positive it tells you what drug it picked up. However, that will mostly just trigger a thorough search and if they fail to find anything you are good to go. Unless of course you are acting super suspicious. Jul 31, 2018 at 13:14
  • @npl: Note that Canada switched completely to polymer banknotes in 2013, and I would guess (though I haven't found confirmation online) that drug residue doesn't "stick" to them as much as it does to traditional paper bills. Jul 31, 2018 at 19:33
  • 1
    You are probably fine if it is domestic flight. If worst comes to worst, you would just need to call an attorney. If it is an international flight, I would use a different bag because crimes like that, which harm the entire society, are actually punishable by death in many places that Canadair flies. It costs less than 100 US dollars to prevent problems like that completely.
    – Abdul Ahad
    Jul 31, 2018 at 21:19

5 Answers 5


Just because your bag is triggered doesn't mean you will be in trouble. I bought a backpack at Heathrow duty free while in transit to the US which triggered a positive hit on the explosive wand - while it was still in the plastic.

It got swiped twice, detected twice, and then the inspector looked at it and just let me through, no muss no fuss.

In your case, I would get a copy of the police report as an extra assurance, but I would not worry about it.

Many things will trigger positive, such as remnants of poppy seed bagels and inspectors are trained to look for these and make a holistic determination as to the passenger's risk profile.

  • 41
    "get a copy of the police report as an extra assurance" That's exactly what I'd do.
    – RonJohn
    Jul 29, 2018 at 23:48
  • 29
    And bring some extra time.
    – DonQuiKong
    Jul 30, 2018 at 6:56
  • 4
    @RonJohn I'm confused why. Is it illegal in Canada to use drugs in a jurisdiction where it is legal? If not, why would "this backpack contained drugs at some non-determinate point in time" be a problem in any case? Sure, they'll make extra sure that you don't carry drugs right now (so extra time sounds sensible), but I don't see what else they'd want from you.
    – Voo
    Jul 30, 2018 at 14:31
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    @Voo cops -- even Canadian cops -- can be... unpredictable. If the dog smells drugs on the backpack, they might listen to OPs story, or... having heard so much BS so many times it would make your head swim, they might decide OP is lying dig through everything, including bodily cavities.
    – RonJohn
    Jul 30, 2018 at 15:31
  • 5
    Would a police report from some time ago stating that the OP had volunteered some drugs but they took no further action actually help? This bag held drugs at some point, but the police then didn't do anything, so of course it must be OK now, mustn't it, officer? Jul 30, 2018 at 18:58

Is it likely that a scanner or swab or whatever those silver wand things are would pick up any trace of that stuff?

Both drug detecting machines and sniffer dogs operate within the physical realities of our world rather than in a magical CSI-like universe. Therefore unless your backpack still has a sealed compartment with hidden drugs, it is extremely unlikely any sensor would be able to pick up any traces after you've throughly washed it in a washing machine. Remember that pretty much anything contains a trace of drugs these days, so even if a machine is sensitive enough to figure out drugs have been in your possession at some point of time, it would likely be set to a higher threshold to avoid false positives from the majority of travelers.

Relax and enjoy your backpack.

  • 2
    I think you underestimate the sensitive of some animals and machines. Especially smell is something where animals can and do surprise us constantly.
    – Tom
    Jul 30, 2018 at 7:34
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    @Tom if the dog is sensitive enough to smell trace amounts of a drug on a backpack that was thoroughly washed, its going to smell false positives everywhere. They're also far less effective than claimed by the authorities (see my links for references).
    – JonathanReez
    Jul 30, 2018 at 7:38
  • 2
    They're not magical for sure. However, I assure you that cats can still smell some things after washing it once with regular detergent (as was done here). I would be surprised if dogs were very different, but I don't own a sniffer dog.
    – Tom
    Jul 30, 2018 at 7:43
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    @Tom The matter is not if the dogs can technically smell it but rather if they are trained to react to such small traces.
    – zakinster
    Jul 30, 2018 at 8:50
  • 3
    If this "mom of one" named Elizabeth is in actuality figity, nervous, brown and named Elizabeta, she might get scrutinized a bit more. Or not, if the cops fear a lawsuit. Better to be safe than sorry.
    – RonJohn
    Jul 30, 2018 at 15:36

They do have swabs and machines that can detect traces of hard drugs at Canadian airports, but they're going to be most likely checking on arrival (that may change after October 17, 2018) and you have what is likely a good enough story assuming there's nothing there to find.

You'd have to be very unlucky (or be doing something to stand out) to even get that treatment unless they're suspicious for some other reason. The only time I've seen them is on the Border Security TV show, whereas I've been swabbed for explosives a couple times and often have my carry on rifled through because of all the weird things I carry. People I know have had problems because of residue on their shoes and clothes (from various legitimate activities) that light up the explosives detectors.

  • 5
    I used to trigger the explosives detectors every flight when still using slide film. The celluloid film base was similar enough to nitrocelluloid based explosives to set off the equipment. Never had a problem, they knew the false positives well enough
    – jwenting
    Jul 30, 2018 at 11:11
  • 1
    What's so special about October 17th? Jul 31, 2018 at 9:00
  • 1
    @BurhanKhalid Pot becomes (federally) legal in Canada on that day, so there may be more vigilance in preventing export. I believe the Netherlands has some such controls. If they're looking for pot, they'll look for illegal drugs too. Jul 31, 2018 at 12:41

In Montreal, as I went through the full body scan machine and my baggage and backpack through the baggage scan, something was set off. I then was patted down by a female agent, all my baggage was searched by a young male agent, each rolled-up article of clothing unrolled, all my camera equipment, each part of the baggage and articles.

Finally, when I asked they said it was probably a "trace" of some chemical, "Tetracyl or Tetraxyl" was found. When they asked where and at what job I worked and heard I was a nurse at a large health centre in Montreal, they said that must be it! (in psychiatry but I do give liquid long-acting injectable antipsychotics, so maybe that was it).

They also asked what medication I take... Fortunately, I arrived at the airport early but I was in shock after and barely got to my gate! It did not help that in the past the procedure of placing stuff in bins mixed up with others meant my laptop was picked up by someone else! So I was already anxious so maintain your cool!


Domestic travel:

Swabbing is primarily for explosive residue. With the changing laws, swabbing for drugs at the terminal entrance would not be practical.

International travel into Canada:

Perhaps nothing or you can be denied entry under the suspicion that you will use drugs in the country.

If you can find it, there is a TV show Border Patrol where you will see this scenario come up several times.

The traveler is always thoroughly searched, then the border officers will make a decision.

  • If the residue in question is marijuana, that's now legal in Canada. Dec 13, 2018 at 21:23
  • 2
    @jpatokal This has been on the show. CBP freely says that while cannabis is legal to posses and use in Canada, it's still illegal to cross the border so the traveler still gets searched. OP mentioned specifically 'hard drugs' though which would still be treated as such.
    – DTRT
    Dec 13, 2018 at 21:29
  • The OP does not say they're crossing the border. Dec 14, 2018 at 2:34
  • @jpatokal You are right. Swab + drugs most frequently means a border inspection as swabbing in domestic travel is primarily for explosive residue.
    – DTRT
    Dec 14, 2018 at 14:56

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