[Stet123]

Not sure if this is the right place to be posting this but figured somebody on here may be able to help. I have a plastic Yeti cooler that has a really bad, lasting smell from dead fish and bait that got left in there for too long. The smell is extremely hard to remove, I’ve tried ozone generator, bleach, baking soda, vinegar, etc. These seemed to help a little bit but the smell always comes back. Is anybody able to tell me what’s going on here from a chemistry standpoint and is there any hope for salvaging this or should I just pitch and get a new one? (I’d really like to try any route possible to save it as it’s a customized cooler and very expensive)

Thanks!

[Corribus]

The interior of the Yeti is plastic, which is porous. Odor molecules (in this case probably long chain amines) essentially get trapped within the polymer lining, and reach an equilibrium with the interior headspace when it is closed, so when you open it, you get a nice whiff. Odor threshold for these is pretty low, so it doesn't take much to stink. And surface cleaning won't really help, because the molecules that give the bad smell are literally absorbed on the interior of the polymer. The only way to really get rid of it is to literally air it out. You'll just want to open it as wide as possible and let it sit in a warm, well-ventilated spot. It may take a while, but eventually it should lose its smell.

[Stet123]

Gotcha! That makes sense. How long do you think it would take to air it out? Would it help if I put it in the sun or does it just need lots of time open? Or is there anything else I can do to help expedite it? Thanks a lot!

[rolnor]

 A hair-dryer?

[Stet123]

A hair-dryer?

Why would a hairdryer help? Cause of heat?

[Corribus]

You just want to maximize the number of air-replacement cycles. Keeping the concentration of odorant in the container low maximizes the rate of diffusion of substance out of the polymer. Keeping it warm will also increase the rate. But I'm not sure this will happen over the timescale that you could use a hair dryer. It may take days to weeks.

Your best bet would be to set up some kind of blower with a hose at the end and direct the hose into the container and just let it blow for a few days.

[Stet123]

So having it sit in my basement with the lid closed all winter probably didn't help. Lol.

Sounds like best bet is to just let it sit with the lid open(in the sun) for extended period of time.

Thanks!

[Corribus]

Yes, more or less. I wouldn't sit it in direct sun, that's never good for plastics long term. Just somewhere well-ventilated, warmish. Remember, if you can smell it, it's in the air, which means it's some has left the plastic. Eventually enough will dissipate that you won't be able to smell it any more.

[DiMiTri]

Hi,

If you don't have time you could opt for masking the odour. This will not remove it but instead of a fishy smell greeting you, it will be a fresh lemon smell. Limonene seems suitable for this.

Cheers,
D

[pcm81]

I agree 100% with the advice to let it air out as well as to keep it out of direct sunlight.

This thread reminded me of something i thought of a while ago. If you have some sort of contamination, which is a problem when you do X, then doing X' should eventually get rid of the problem. In your case sniffing air that is coming off the inside of a cooler is a problem due to cooler "contaminating" that air (X). So by getting allot of air through the cooler (X') you in effect wear out the problem.

Here is an extreme case scenario: if i am trapped on an empty island and all i have to drink out of is a glass that had oil and other nasty stuff in it, i am going to do my best to wash it out with clean water (assuming i do not have soap or other surfactants available) which will be a huge hassle to get it completely clean, but if whatever is left in that glass i cant get out with water, then the water i will be drinking from it wont get that nasty stuff in my body either. I am NOT suggesting that is is safe to drink from your chemistry set glassware or that you should drink from oily glass, but my point is that if doing X (drinking water from glass) is a problem due to contamination, by doing X' (washing glass out with water) will eventually get rid of contamination. In your case airing the cooler out is X'.

I'd also suggest placing a fan in front of the cooler with back of the fan directed at the cooler, so that fan is sucking air out of the cooler. By reducing pressure in the cooler you may accelerate the scent inducing molecules to leave the surface. Shoot, you can probably just stick a vacuum hose in the cooler and tape the lid, so vacuum is sucking air out of the cooler.

EDIT: don't let the difference in advice of blowing air in vs sucking the air out confuse you. It will all work the same, it comes down to air replacement cycles as stated above. The reason why i suggested vacuum hose sucking air out is because this should reduce pressure inside the cooler, hopefully accelerating the rate at which scent inducing molecules leave plastic. How pronounced this effect be as compared to blowing air in, i can't tell you.

[Stet123]

I agree 100% with the advice to let it air out as well as to keep it out of direct sunlight.

This thread reminded me of something i thought of a while ago. If you have some sort of contamination, which is a problem when you do X, then doing X' should eventually get rid of the problem. In your case sniffing air that is coming off the inside of a cooler is a problem due to cooler "contaminating" that air (X). So by getting allot of air through the cooler (X') you in effect wear out the problem.

Here is an extreme case scenario: if i am trapped on an empty island and all i have to drink out of is a glass that had oil and other nasty stuff in it, i am going to do my best to wash it out with clean water (assuming i do not have soap or other surfactants available) which will be a huge hassle to get it completely clean, but if whatever is left in that glass i cant get out with water, then the water i will be drinking from it wont get that nasty stuff in my body either. I am NOT suggesting that is is safe to drink from your chemistry set glassware or that you should drink from oily glass, but my point is that if doing X (drinking water from glass) is a problem due to contamination, by doing X' (washing glass out with water) will eventually get rid of contamination. In your case airing the cooler out is X'.

I'd also suggest placing a fan in front of the cooler with back of the fan directed at the cooler, so that fan is sucking air out of the cooler. By reducing pressure in the cooler you may accelerate the scent inducing molecules to leave the surface. Shoot, you can probably just stick a vacuum hose in the cooler and tape the lid, so vacuum is sucking air out of the cooler.

EDIT: don't let the difference in advice of blowing air in vs sucking the air out confuse you. It will all work the same, it comes down to air replacement cycles as stated above. The reason why i suggested vacuum hose sucking air out is because this should reduce pressure inside the cooler, hopefully accelerating the rate at which scent inducing molecules leave plastic. How pronounced this effect be as compared to blowing air in, i can't tell you.

Appreciate the response. That's interesting. Well I have had the cooler open in my room with window open above it for the last 5 days and just playing the waiting game, seems to have made minimal progress but I'm guessing this could take some time as stated above by someone else. My fear is the odor molecules(amines) have become permanently trapped or sealed into the porus..? Is this something that's even possible? Thanks

[Borek]

My fear is the odor molecules(amines) have become permanently trapped or sealed into the porus..?

If they are permanently trapped (not impossible) they can't be smelled. As long as it stinks it means they are released, so in the end it will be clear of them.

[Corribus]

You have to remember also that the process of decreasing the concentration in the headspace is not linear in terms of rate. The rate of transfer out of the polymer slows (decelerates) as the concentration inside the polymer gets lower - because the rate is correlated to the difference in concentration across the polymer/air interface. By maintaining as low a concentration as possible on the air side, you can maximize the rate (hence the air replacement cycles), but there's nothing you can do about the lowering concentration in the polymer. So there's no avoiding the fact that the process is slow and will get slower as a function of time. In principle, you never reach zero concentration. But you aren't trying to get to zero, you're trying to get below the odor detection threshold. Point being that you will probably go through a (long) phase where it doesn't seem like there is any improvement because the changes are so small your nose won't get detect them. Actually what will probably happen is you'll reach a point where you feel it's "good enough to use". But again it may take quite a while to get there because the nose is very sensitive to these kinds of "rotting fish" molecules - for good reason as they can be a food safety indicator. 

[Stet123]

You have to remember also that the process of decreasing the concentration in the headspace is not linear in terms of rate. The rate of transfer out of the polymer slows (decelerates) as the concentration inside the polymer gets lower - because the rate is correlated to the difference in concentration across the polymer/air interface. By maintaining as low a concentration as possible on the air side, you can maximize the rate (hence the air replacement cycles), but there's nothing you can do about the lowering concentration in the polymer. So there's no avoiding the fact that the process is slow and will get slower as a function of time. In principle, you never reach zero concentration. But you aren't trying to get to zero, you're trying to get below the odor detection threshold. Point being that you will probably go through a (long) phase where it doesn't seem like there is any improvement because the changes are so small your nose won't get detect them. Actually what will probably happen is you'll reach a point where you feel it's "good enough to use". But again it may take quite a while to get there because the nose is very sensitive to these kinds of "rotting fish" molecules - for good reason as they can be a food safety indicator.

Very interesting, thanks for the reply. It does seem to be making some small progress after checking on it after this weekend. It’s definitely better now, hoping in a couple weeks it’ll be back to about normal.