What's the vaporization temperature of mouse urine?
Let's say I hypothetically had some mice pee in some plastic components that cannot be properly cleaned in any realistic way. Is it possible to heat it up to "cook off" the mouse pee nastiness without actually melting the plastic?
Get some enzyme spray specifically for addressing pet urine. There are lots of varieties online from pet warehouse places. Nature’s Miracle is a popular one. Get the urine destroyer, the stain and odour eliminator isn’t as good.
It actually breaks down the urine residue as opposed to the other suggestions here which mask or encapsulate the smell without addressing the source.
I have used enzyme on quite a few things I thought would never be usable again - def worth their weight in gold in my experience.
Since you mention this is a vehicle, I think the ozone generator approach is probably easiest.
I've had vehicles with similar issues, and open windows + time really did it. An ozone generator is the faster version of what I've done.
Just don't let it go crazy, as ozone attacks pretty much most materials in a car. So maybe throw a generator in it, let it run for a couple hours (put a small fan in the car to really circulate it up under the dash), then air out the car well.
The idea is the urine is probably more reactive to the ozone than anything else, so get it reacting. Then stop and clear the air before it has too much time/concentration to start on the plastics.
If urine is in the carpet, use the enzyme with an upholstery cleaner (similar to a carpet cleaner) - then you'll be pulling the nasty out with vacuum.
Enzymatic cleaner is amazingly effective. Used it in a camper that had mouse nests everywhere.
So I had a similar issue in the past that I used an ozone generator for... all of my upholstery just unglued itself. So this is one of the solutions that has been suggested among "just torch the thing and collect the hefty insurance on" that I am trying not to do lol... but enzymatics have been suggested elsewhere and apparently have come a long way. That's definitely my next try.
ozone is an oxidizing agent. it destroys smells by oxidizing the proteins and such that create the smell.
Unfortunately, this also means that any plastics or adhesives used will generally be broken down too. (the degradation in plastic is similar in effect to UV exposure, where the adhesives just... as you mentioned... becomes 'unglued')
Enzymatic cleansers will likely be a better solution. Though, I've used ozone generators to remove some truly.... unique... smells; when I was working for a college cleaning dormitories. but it really is a nuclear option.
Most ducting in the dash of vehicles can be accessed with just a screwdriver, and there are usually only a handful of screws and plastic fasteners/snaps you have to remove. Downloading the diagram from a shop manual will show you where they are so you don’t have to find each of them, but it’s usually apparent in situ.
If you don’t remove the ducts to clean them, while you may be able to lessen the smell by removing vent covers and snaking cleaning materials through the ductwork, your car will still always smell. The only way to get rid of the smell entirely is to remove the affected ducts and properly wash them.
Before any if that, however: do you know which ducts are affected? It will reduce your workload considerably, especially if the affected duct is in fact your fresh air intake, as I would expect.
The way I would determine that is to
run the fan on high with recirculate ON and all windows open for several minutes, then
sit inside and close the windows. Is the smell lessened from before?
If so, confirm the diagnosis by turning recirculate off. If the smell suddenly gets stronger, it’s likely the rodent never made it past the blower manifold.
In that case you’re in luck, as you may not need to disassemble the dash much at all. (You would be working mostly in the engine compartment and passenger footwell.)
It's two separate questions I guess, where the answer, would answer both.
As for the more pressing issue. It's inside some automotive internal stuff, that just wouldn't be worth the time or expense to remove it. I really want to retain the vehicle for limited use cases, mice no longer are in the vehicle, but the odor is bad.
I don't necessarily expect to eliminate the odor 100%, but any reduction to the point where you don't feel like your breathing in some measuruable amount of mouse urea would be nice...
Look into ozone generators or ozium air fresheners. Ozone generators sanitize without heat and help reduce odors but might be expensive and take a long time to be effective (hours to days). Ozium air fresheners absorb the odor and they got the gasoline smell out of my car, no idea how they work but you just leave them in your car.
So, I have no clue what exactly it is that you want to heat and how you would do it (I somehow imagine you trying to put a microwave over the steering wheel of a car or blow drying your radio) but as for whether it would work to eliminate the odor that is bothering you... I am no expert on mouse urine smell but I did work with GC and judging from GC-O measurements you need to go up quite over 100°C to make every molecule that gives off smell volatile. So my guess would be, no, you cannot cook off the smell. My guess is even if you literally boiled a cup of mouse urine for an hour on a stove and let it cool down it would still have some odor left.
That being said, I very much hope I am wrong and you or someone else will prove otherwise!
The way I would go about it is probably to use something like Febreze, basically trying to put the odor molecule into a complex (is this how Febreze works?) where it either cannot bind to your receptors anymore or isn't volatile anymore. Probably do all of it, first blow dry (?) and heat off what you can, then use some H2O2 spray if the plastic allows it first (might even get some stuff to oxidize and change its properties i.e. the smell), then blow dry (?) it again to heat off what you can, then use an odor neutralizer.
You pretty much either put so much heat into urea that it turns to ammonia and melts your plastic while doing so or you wait for some bacteria to eat it and turn it into ammonia. It technically starts vaporizing at above 130 C.
It's a couple different things, but one of them is automotive plastics. There is just no way to get to parts without tearing the entire thing apart, and I don't have the time or technical skills to do it quickly. And even if I did, I am not sure if it would really be worth it because of how infrequently it's used.
You might be able to soak it in some kind of water/soap or isopropyl bath and then dry it. If it has electronics it might not be doable without taking things apart