We also tested WD-40 to see if it worked at hiding scratches – as the manufacturer and countless You Tubers claim
Here are 10 things to remember next time you tackle a troublesome car scratch.
1. WD-40 does work... sort of
WD-40 stops squeaks, loosens rusted parts, frees sticky mechanisms – but it also hides shallow scratches.
However, we found that it takes four applications to make a noticeable difference and it will wash away the next time you clean the car.
Drive smarter and cut your costs.2. Most scratch removers only remove shallow scratches
There are three types of scratches that can affect a car panel:
Shallow scratchMedium scratchDeep scratchMost car scratch removers are designed to take care of shallow scratches, scuffs and swirl marks.
Some of the products we tested faded the appearance of medium scratches, but none of them worked on deep scratches. However, keep in mind that they don't claim to work on anything more than a shallow scratch.
If you identify a deep scratch on your car, it may be time to turn to a professional. Depending on the level of damage, a bodywork repair shop will either be able to smooth it out or, if need be, replace the car panel.
How to identify your scratch
If you spot a scratch on your car, but can't tell how deep it is by sight, use this easy method to identify it.
Pass your fingernail over the mark. If your fingernail gets caught, this is a medium scratch at least.
With deep scratches, you'll see the primer or metal itself showing through.
3. You don't always need to pay more
We tested a range of car scratch removers priced between £2.10 per 100ml (T-Cut Rapid Scratch Remover) and £11.36 per 100ml (Autoglym Complete Scratch Removal Kit).
4. Some repairs don't last long
We investigated whether the car scratch removers we tested would survive a hand wash after their application.
We applied the products, let them dry and then washed the panel five times with car shampoo.
For the majority of the products we tested, the scratches reappeared before the five washes were up:
5. Washing creates a better finish
Once you've used a car scratch remover that gives you good results, you may nonetheless be dismayed to find the area of bodywork you've worked on left with a bit of a haze.
This duller finish is nothing to worry about. Give your car a once-over with a good polish and you'll be that much happier with the end results.
6. You shouldn't need extra tools
Some car scratch removers can be used with an electric car polisher on deeper scratches.
We found that using a polisher didn't do a significantly better job at removing these types of scratches compared to applying the products by hand with a microfibre cloth.
If you have scratches that get into your paintwork, we'd recommend taking your car to a garage for a better result.
7. Preparation is key
One thing we can't recommend highly enough is prepping the area you're going to work on with the car scratch removers.
By prepping, we mean washing the vehicle with car shampoo to make sure there's no lurking grit. If this isn't done there is a risk that rubbing a foam pad or microfibre cloth over the area, with grit or sand on it, could make the scratches worse.
8. Avoid using on a sunny day
Not all car scratch removers do well when applied in direct sunlight. If this is the case, they do say so in their instructions.
9. Take your time
We found many car scratch removers need more than one application to get rid of the shallow scratch.
10. Do a test run
Many of the scratch removers we tested suggest applying the product to a small out-of-the-way area first. This is to make sure it reacts well with your paint job.
It will say in the instructions if you need to do this.
source https://www.which.co.uk/news/article/does-wd40-remove-car-scratches-and-nine-other-things-we-learned-testing-car-scratch-removers-aax9P0U2Ldh8