Car Smell Removal FAQ

This 'Frequently Asked Questions' page should answer most of your questions and clear up some of the old wives' tales about odour removal.

1. How do I get rid of a dog smell in my car?
2. How do you get cigarette smoke smell out of a car?
3. How to get rid of a musty smell in a car?
4. How to remove the smell of sour milk?
5. How to remove the smell of vomit?
6. How to remove the urine smell?
7. How do I get rid of a burning smell when the heater is on?
8. I have tried everything... why can't I get rid of the smell?
9. Why do I get a smell only 'sometimes'?
10. Does baking soda work to remove smells?
11. Do air fresheners work?
12. What is this 'pairing' that you keep mentioning?

How do I get rid of a dog smell in my car?

A dog in a truck.

Dog smells are usually caused when the natural oils in a dog's coat contaminate your car. Bacteria love to feed on it. The first stage in removing dog smells is to clean the car, which will mean shampooing all the seats and carpets, taking great care to remove as many dog hairs as possible. This is easier said than done, as they tend to weave themselves into the fabric of your upholstery. The best way to do this is with a rubber brush... that is, a brush with bristles made of rubber, but still, it is time consuming. With most of the dog contamination removed from the car, we would use an enzyme product which when added to a damp car sets about eating what is left. If the enzymes eat the dog oils, then there is nothing left for bacteria to feed on, effectively curing the problem.

However, at this stage there may be a slight doggy whiff remaining as some of the bacteria may remain, a some people may still be able to smell it faintly. The solution to this would be to fog the car with Cherry. This is a technique called pairing which is explained further down the page.

How do you get cigarette smoke smell out of a car?

A British Bulldog smoking a cigar in a car.

The smoke smell comes from two sources, the first is from cigarette ash, which gets everywhere, making cigarette odours one of the hardest to remove. The second comes from tar, contrary to popular opinion and marketing hype, cigarette odours don't really 'get into' your fabrics and upholstery, instead they adhere too hard (and especially cold) surfaces like glass, metal and plastic. So, as always, the first stage in a smoke odour removal is a damn good clean!

Unfortunately, to remove ALL the ash, and clean ALL hard surfaces would mean dismantling much of the interior of the car, which isn't really cost effective or practical, especially as it isn't always necessary. Unfortunately, you don't really know until you try. So, Cigarette odour removal has a certain element of trial and error.

Rather than dismantle the car to get to hard surfaces, we use a different technique, which is to attempt to seal them. This is done with ozone or fogging. As an example, imagine that there is tar which has wafted up behind the dashboard, and some ash which has fallen into cracks and ended up back there, the ozone will reach this and oxidize the surface or fog will soak in and dry hard. Technically, we haven't removed the source of the smell, but the surface of it is no longer usable by bacteria, so it is sort of sealed in. As long as it isn't disturbed, it won't smell much.

We will also use an enzyme and pairing. After this, we will send you away, hopefully with your problem cured. But we phone after a couple of weeks to ask you how you are getting on. If the smell is still there, we invite you back to let us have another go.

How to get rid of a musty smell in a car?

Quite simply, this type of mildew and mouldy smell is caused by damp getting into your car, this may be dirty water, or it may be water that combines with dirt already in your car. Either way, you end up with a soup which is a rich breading ground for mould, mildew and bacteria which stinks up your car.

The first thing to do is to figure out how or why your car is damp. It may be that your car was caught in a slight flood, or you left a window open on a rainy day, in which case no further action is required. However, if you have a leaky windscreen, then you'll need to get this fixed or else the problem will just return. Another problem can be condensation, in which case you'll need to change your habits in regard to the controls on your heater.

Once the car is cleaned, disinfected and dried, the cause of the smell should be no more. To deal with any lingering smells, we fog the car with mint.

How to remove the smell of sour milk?

This is a really nasty odour to remove, and if you spill milk, get in touch with us for an accident clean. Essentially, you need to remove the milk... all of it!

When milk does get spilt, it often happens in the boot, which means that it can end up in the spare wheel compartment and down the back of the rear seats. Usually, we will need to take the rear carpet out and sometimes the back seats, wash it all and dry it. Even if your spillage happened months ago, this is often the best course of action. What we can't locate and clean is dealt with by enzyme treatment (like friendly bacteria). Over a day or so, the enzymes will eat all the milk, causing the stinky bacteria to starve and die... at which point the enzymes eat them too.

A panda car. The police have all sorts of unsavoury types in the backs of their cars.  After a long stake out, the front might not be all that fresh either. 

How to remove the smell of vomit?

We do it in much the same way as we deal with sour milk -- by cleaning and enzymes. Vomit can contain corrosive acids which can cause lasting damage to your car, and so it is important to clean up and wash out as quickly as you possibly can.

How to remove the urine smell?

We have first to locate the contaminated area, at which point we soak it with a special industrial product designed only of urine. We then shampoo the area and use an extractor to wash it all out, and then we apply more of the anti-urine product.

As with sour milk and vomit, we aren't really tackling the smell at all, we go straight to the source of the problem and use special products to eliminate it. This will cure the problem of the smell, but as always, we can provide a deodorant to mask any lingering whiffs until they fade completely.

How do I get rid of a burning smell when the heater is on?

Speaking personally, this is a problem I'm unable to tolerate as it causes me severe headaches, so I do sympathize. As a pun on 'that new car smell', this is what is jokingly referred to as 'That British car smell' -- the odour of toasted wiring loom and the smell of mildew because the sunroof leaks. The British car industry has got around these problems by going out of business, but it does occur with some other cars.

If your car has air conditioning that suffers from odours, I'd suggest having the air-con serviced, which some companies and dealerships can provide for a reasonable amount of money. But if it's just the burning smell, then complain to the dealership. It may be something they can fix, but possibly not. Unfortunately, it's not something that we at New Again have a cure for.

I have tried everything... why can't I get rid of the smell?

The answer is simply that you haven't removed the source of the smell. You may have attempted to clean it up, but your attempts may have only succeeded in diluting it and spreading it further. This really is the only answer to most odours.

From watching some TV adverts, you may well be forgiven for thinking that all you have to do to remove an odour is to buy a bottle of product and spray it around -- this is just marketing hype, I'm afraid. While some of these household products will disinfect as well as just provide a nice smell to mask your nasty niffs, even a disinfectant is just a temporary fix. Sooner or later, the odour will come back, and you'll have to go out and buy more household products... which obviously suits the manufacturers just fine. That's not to say that household products are useless, or bad... many are very good, but they are not going to work as advertised when up against serious odours.

If it were easy, everyone would be doing it, and we wouldn't have needed to write this FAQ. For many people, it's just easier to use a professional odour removal service. 

Why do I get a smell only 'sometimes'?

As you should have gathered by now, most odours are caused by bacteria. Bacteria thrives when it's warm and damp. But it doesn't thrive which it's too dry, too cold or too hot.

So if you notice a smell sometimes, it's probably because it's a nice warm day, or it's a cold day, but you had the heater on for a change, or some other combination of factors which suddenly caused a population explosion of the bacteria.

If you are getting intermittent problems, taking as a warning and address it. To remove the source of the smell, first you have to find it. Take this opportunity, sniff out the problem.

Does baking soda work to remove smells?

Yes it does, or at least it can do -- it very much depends on the situation. Sodium bicarbonate, can have its uses, especially against musty smells and even cigarette ash. It also works on other kinds of odour, but can take time and there are other products that are quicker and more effective. We have odour absorbing crystals of various types that are especially designed for the work we do, even so, Baking Soda is still something we use on a fairly regular basis.

Do air fresheners work?

A forest of little tree air fresheners.

The simple answer is no. Air fresheners do not freshen air. Although they may employ chemicals which are designed to disinfect, absorb odours, or even impair your sense of smell, they are not very effective and most of them do little more than emit a pleasant smell that will mask unpleasant smells.

Odours are often compared to musical notes, and I will continue the analogy by saying that using an air freshener is a bit like trying to solve your problem of noisy neighbours by turning up your stereo.

However, that is not to say they don't have their uses. As long as they are emitting a pleasant smell (and not other harmful chemicals, thanks very much) then they are quite nice to have -- who doesn't like a nice smell? For us here at New Again, we do have some very powerful air fresheners, deodorizers and odour bombs... which we can put into a car, will deodorize, and will linger.

We aim not to mask smells but to remove them... but this doesn't always happen overnight (enzymes can take 24–48 hours to work to be exact) and sometimes it's nice to have something to mask foul odours while they subside.

In cases where we are unable to completely remove a smell, we use a technique called pairing. You may think we are splitting hairs as we do add a nice smell to the car, but rather than masking bad odours, the technique alters them.

What is this 'pairing' that you keep mentioning?

This is a technique where you match a nice smell to a nasty smell in order to change the way you perceive it.

Most of us take smell for granted... we all do it, but we don't have much understanding of it, nor much of a vocabulary for describing it, so it makes this difficult to explain.

One way of describing pairing is to say that few of us would sit around eating cloves. They are not exactly tasty, but add a lot of apple and pie to the cloves, and you have a really nice flavour.

There aren't actually that many different odourant substances that can be detected by humans (compared to some other animals), they are often called flavours or notes. In either analogy, they are like ingredients, and with most ingredients, they can be nice or nasty depending on the context.

For example, many odourants that make up the smell of mildew are also found in the smell of mint. So if you add the smell of mint to a car that smells of mildew, you will just end up with the smell of mint. You aren't trying to overpower the smell of mildew by adding a louder smell, instead you are blending, and the mildew smell becomes a part of the mint smell.

Another way to describe this is to think of a constant, irritating hum or tapping noise. You could try and drown this out by playing loud music over the top of it, but if you play gentle music which is in the same key or same beat, the hum or tapping can become part of the music.

Yet another way to think of it is with coloured paint. Imagine you have a blob of blue paint, and you mix green paint with it, you will end up with green. Blue is an ingredient of green, so when you mix the two, the green may change in hue, but it's still green and it certainly isn't blue any longer.

Obviously, it's not quite the same thing, the most significant difference is that there are only three primary colours and three secondary colours, and there are 6-7 different smells. But by taking a scientific approach to it much the same effect can be achieved.

by Danny Argent
technical writer and customer education.

Related Videos

You bought a smelly car?

Removing odours from car interiors

Video Tags: #OdourRemoval