The process of car cleaning is far more complex but effective than it used to be, and finding the best prewash is the perfect example of this. Pre-soaking a car with chemicals before you shampoo is an important step for dislodging muck and grime. Pre-wash is excellent, you spray it on, then wash it off. It's not quite as fancy-looking as a good snow foam, but it'll help remove grease and dislodge embedded deposits without being a co*cktail of abrasive co*cktails that can dull your paint over time (like a traffic film remover).
©CAR
If you've consumed at least one or two therapeutic car detailing videos, you'll notice that professionals use pre-wash before the therapeutic snow foam to lift off the thickest and grimiest of dirt. While you won't find us on Tik Tok, we decided to organise the ultimate pre-wash test of our own: remove years of moss, dirt, and algae from a 1982 Audi 80 CD. A rare five-cylinder version that at the time of writing, hasn't been taxed since 1996. Editor's pick: Car Gods 54 Almighty Pre-Wash - buy from Amazon We took each product and applied it panel-by-panel before judging the effects. We then took our favourite pre-wash and proceeded with it to cover the remaining bits of the car before giving it a full wash and detail with our various car cleaning kit products. Needless to say, it looked like a different car once completed.The best car prewash 2024 at a glance:
Best budget pre-wash: ValetPro Citrus Pre-Wash - buy from Amazon
Best car cleaning sprayer: Autoglym Easy Sprayer - buy from AmazonThe best car prewash 2024
Description
As pre-washes go, few come close to the sheer grime-removing power of this product from Car Gods. A few sprays over the thick dirt, and gone was the filth that plagued the even greener Audi.
It boasts pretty good value for the quantity you get, is safe to use on a number of surfaces from plastic to metal and even carbon fibre. It's great for removing loose dirt, bug deposits, and other detritus on the paintwork. If you're on the market for a pre-wash to enhance your inner detailer on the best level, you really should be getting an order in for one of these.
Pros
- Pretty good value for money
- Effortlessly removed the worst dirt and grime on our test subject
- You get a decent amount of quantity
Cons
- Be careful not to spray too much at once
- Can leave streaks if you don't rinse straight away
Best all-purpose cleaner
Via Autoglym
Description
All-purpose cleaners (APCs) are never as strong as dedicated pre-washes, but Autoglym say you can use this APC to 'pre-soak' a car before getting on with the full wash. So with that in mind, we decided to give it a try.
Unfortunately however, despite a few sprays, it didn't quite impress as much as the other products tested. It felt weaker, less capable, and as if the Audi was a little too much for it. It's fair to suggest that a seriously mucky car is too much for any pre-wash, but the others did the job just fine, and the Autoglym APC let the side down slightly. With that said, it is a versatile product if you want to clean up other areas of the car including the interior. That is something the others can't match.
Pros
- Very versatile
- Reasonably good value
- Perfect for quick sprucing
Cons
- No good on very filthy cars
- Easy to get through bottle
Description
A premium prewash that's designed to shift more embedded bits of dirt, this is the Bug and Grime Remover from Auto Finesse. Safe on waxes and sealant, this spray is effective at removing embedded dirt and grime and can even be used to degrease engine bays.
We used this one to clean the almost-black fuel filler cap of the Audi as well as the rear quarter panel, after two sprays and a rinse, it was clear as day and it felt safe to touch. It represents good value, too. It's one of the cheapest products on our test, and it impressed massively.
Pros
- Powerful cleaner that won't strip protectants
- Quite good value
- Great for cleaning fuel doors
Cons
- Takes a few sprays to get every last bit
Description
Some pre-washes need diluting. This simply means you pour a small portion into a measuring bottle before mixing with water. Duel Autocare's Nitty Gritty is one of them, and we poured a bit into the Autoglym Easy Sprayer. The results were pretty impressive.
Granted, the bonnet and roof are arguably the worst parts of a dirty car and possibly the hardest to clean since the most amount of elements hit them. But the Nitty Gritty dealt with the dirt really very well. It's just as good that the product is efficient because you don't get an awful lot at a 500ml capacity. You did however, have to agitate loads of it in order for it to work, and it just wasn't quite as effortless as the Car Gods and Auto Finesse products.
Pros
- Very effective in a spray bottle (when diluted)
- Most efficient to use out of the lot
- Cuts through thick dirt pretty well
Cons
- Doesn't quite do the job as well as the others
- Panels needed going over a few times
Description
This is a concentrated prewash which makes it a really good value option as one litre will make eight litres of prewash (at an 8:1 dilution ratio). Dilute it into a spray bottle with water and spray it onto your car as you would with any other prewash. We did so on our test and we were pleasantly surprised at how much dirt it managed to lift off.This prewash is alkaline-based (9.5 pH value) to help remove insect and road grime and is infused with orange oil to naturally enhance its cleaning power. Like most other prewashes, it's safe to use on wax and sealants too.
It's a shame it's not pH neutral, so it can be used on everything, but it dealt with a lot considering how filthy that Audi was.
Pros
- Very affordable
- Very capable for its price point
- Very efficient when in use
Cons
- Not biodegradable
- Isn't quite as powerful on the toughest of grime
Description
Our quirky companion of the pre-wash group test came in the form of the Autoglym Easy Sprayer. It's designed to take a diluted sample of cleaning product with water before being equally sprayed along the panel of a car. We weren't expecting too much, but it exceeded our initial thoughts.
You have to pump it several times before spraying, but after enough pumps, you get a paint gun-like application for about 15 seconds. No spray is wasted and you get a decent amount on each panel without using too much. It's a clever tool that really makes application of pre-wash and other things much easier than straining your fingertips with repetitive spray bottles.
Pros
- Durable item with great build quality
- Amazingly effective sprayer
- Works with all sorts of cleaning products
Cons
- You do have to keep pumping it for longer jobs
- It's hard to say it represents good value
It's difficult to pinpoint exactly what prewash is. It's an umbrella term applied to pretty much any product you apply before the shampooing stage. This includes snow foam, all-purpose cleaner , insect and grime remover and traffic film remover. The purpose is that it removes the worst/top layer of dirt and grime before you can proceed with the rest. Detailers use it pretty religiously as well as some prewash integrated snow foams. For this test, we simply took what could be easily diluted and/or sprayed on in order to see if they were any good at removing neglected car dirt. For each product, we agitated the prewash using a soft detailing brush and spread it evenly across each panel. We're talking about a car that can almost be described as 'barn find' condition, so the products had a lot on their shoulders. Prewash is usually added to the name of most snow foams because you use it before washing your car properly with mitts. However proper prewash is different and it's worth knowing what that is. Whereas snow foam is a thick white foam, prewash is translucent. Furthermore, snow foam is at its best when agitating pre-wash. This is so you can agitate it in a contactless way - thus reducing any chances of light scratches. Snow foam also requires a pressure washer and foam lance to work whereas prewash can be sprayed on from the bottle. We've listed our favourite snow foams here, where again, we tested each one panel-by-panel on a brand new Range Rover Sport before measuring the effects.What you need to know about prewash
Just what is prewash?
How is prewash different to snow foam?
How we tested the prewash
©CAR
As briefly mentioned throughout our guide, the challenge was to remove years of dirt, grime, algae and whatever else off a non-running 1982 Audi 80 CD. It had accumulated so much filth, that any standard shampoo wouldn't have gotten to the clean layer of paint hiding beneath. We applied the different prewash products panel by panel and judged the cleanliness of them from there. We then rinsed the prewash using a Worx WG633E Nitro Hydroshot pressure washer (56 Bar) and gave the car a final clean using Autoglym's newly-introduced ceramic shampoo and Bilt Hamber's Auto-Wash. This test was conducted by Aaron Hussain. As a classic car owner who is fastidious about using the right products on them, the Audi test subject was an ideal platform for him. With slightly more delicate paint and trim to deal with, he knew that being careful was key in this test. Aaron Hussain is a commercial content writer at Bauer Media writing for Parkers and CAR. He is obsessed with classic cars and anything with a fascinating story to tell. Just so you know, whilst we may receive a commission or other compensation from the links on this website, we never allow this to influence product selections -read why you should trust usWho tested the prewash?
For verdicts, scoops, news and analysis from the team, delivered direct to your inbox, subscribe to the CAR newsletter.
You can enjoy CAR in its traditional print format, or one of the swelling number of digital editions, optimised for Apple iPhones, Android devices, iPads, tablets and desktop computers.
Just so you know, whilst we may receive a commission or other compensation from the links on this website, we never allow this to influence product selections - read why you should trust us
