How to clean exhaust tips

Exhaust tips are one of those I’s that need to be dotted. Exhaust tips can be difficult to clean due to type of build up that can be found on the inside or the outside of the tips.

Why clean exhaust tips

Detailing a car is about returning it to “as new” condition as much as possible. However, this is not always easy. The exhaust tips can ruin the looks of a detailed car. The paintwork is shiny, the wheels are clean and perfect, but the exhaust tip is black and grey. That won’t do.
Also, some of the newer cars have exhaust tips worked into the bumper, being part of the visual design. Depending on the color of your car, they may stand out by being dirty and contaminated. Cleaning these will improve the look of the car, and will show how much time you’ve spent on details.

Types of dirt found in or on exhaust tips

Both the outside and the inside of an exhaust tip gets exposed to several types of contaminants. The inside of the exhaust tip is mainly covered in carbon deposits from the exhaust fumes. This means it will be covered in a mixture of desposits from nitrogen, water vapour, carbon dioxide, carbon monoxide, hydrocarbons, nitrogen oxides and soot.
The outside of the exhaust tip is covered in a combination or iron fallout, mineral deposits, sand, dirt, tar, acid rain deposits, sand and will likely have some surface imperfections due to the impact with particles thrown up from the road.

How to clean exhaust tips

Before anything can be cleaned, it is important to know what type of dirt you are working with. Knowing the type of contamination helps to find a suitable solution for cleaning.

Inside of exhaust tip

• nitrogen – this will only exist in small quantities, trapped or mixed with the other contaminants. When these are removed, the nitrogen will be removed with them.
• water vapour – this will most likely cause mineral deposits and an occasional rust spot. Clay will be able to remove these if not yet removed by previous cleaning methods.
• carbon dioxide – this chemical is actually soluble in water, meaning any APC or degreaser will have an effect on removing this
• carbon monoxide – is water soluble, meaning any APC or degreaser will have an effect on removing these.
• hydrocarbons – this substance is not soluble in water, but will be dissolved by turpentine, diesel fuel, IPA or benzene (not petrol).
• nitrogen oxide – this will only make up a very small part of the contaminants and will be mixed with the other contaminants. Removing the other contaminants will remove this as well.
• soot – as a form of impure carbon particles, these will be removed in the same way as hydrocarbons. Turpentine, diesel fuel, IPA or benzene will dissolve these fairly quickly.

Overall, a combination of non-polar alkane liquids will be able to remove to most stubborn dirt. A reasonably easy way to use this is to spray this liquid into the inside of the exhaust tips, agitate it with a brush and then wiped off with a paper towel. Either turpentine, diesel fuel, IPA or benzene will do the trick. Some tar&glue removers have certain ingredients that have similar cleaning power.
After cleaning off the worst, it can be followed by a degreaser or strong APC. This will also remove any residue from the previous cleaning step. In the end, it can be followed up by grade 000 steelwool to remove any caked on impurities before polishing the inside with a polish cone.

Outside of exhaust tip

The outside of an exhaust is slightly easier to clean. The contaminants found on here are very similar to those found on a wheel. Using a wheel cleaner can help to remove a lot of the worst contamination. Chemical cleaning such as a tar remover or a fallout remover can remove even more. After this, a good clean with an APC or even regular shampoo will suffice. Claying is always an option if the surface doesn’t feel smooth and clean.
Most exhaust tips are made from metal, meaning polishing with a metal polish shouldn’t be a problem. Rubbing the exhaust tip with grade 000 steelwool may help to smooth the surface and make stone chips less visible. Since an exhaust gives a difficult working area, and removing the exhaust might not be an option it is often useful to either polish by hand, or to use a polish cone as an extension on a cordless drill.