Making your Own Screenwash

If you’re making early starts in December, then the chances are that you’ll appreciate the merits of a good screenwash. Something that isn’t going to freeze in the pipes when the going gets tough, or provide the legionella bacteria with a never-ending holiday camp, in the same way that water might when it’s kept in your tank for years on end.

Since many of us stick gallons of screenwash into our vans every year, especially around winter time, you might be tempted to try and whip up a batch of your own. But given that you can get cheap stuff from concentrate down at your local petrol station, is doing this even worth the effort? We’ll take a look at a few homebrew remedies and see what they’re made of, exactly.

Vinegar
To soak up all that grime and break apart the ice, you’ll want something a little acidic. The best way to do this is with vinegar. We’re thinking the malt stuff that goes on your chips rather than the posh cider stuff that you might drizzle over a salad. Water the stuff down to taste and blast it across your windscreen. What could be easier?

Now, we can see a few problems with this solution. The first is that acids like this might well discolour your paintwork. The second is that it’s probably also going to eat away at the inside of the tubes that feed your windscreen. As such, while vinegar is certainly effective, it’s probably not worth the risk.

Alcohol and Soap
Can you really spray your windscreen with beer and expect it to stay clean? The answer is probably not. But if you get a cheap bottle of vodka from your local branch of Aldi, mix it up with a few gallons of water and a dishwasher tablet, you might well be onto something. But if you use too much soap you’re going to get suds in the mixture, and the stink of booze might well be enough to get you pulled over and breathalysed. If you’re going to use alcohol, we’d suggest the pure, rubbing kind. Dilute as appropriate.

Concentrate
We can’t help but come back to the shop-bought concentrate stuff. It varies considerably in quality, so be sure to check the minimum temperature on the bottle. You want it, ideally, to be effective down to -10°C or lower – that way you’re never going to be caught out during a blizzard. Of course, the freeze-resistance of the screen-wash will depend on the extent to which you’re diluting it. If things are chilly, you can always top the reservoir up with a little bit more of the concentrate.

You can also get ready-mixed bottles. They’re more convenient, but they’re also a lot more expensive in the long-run. Look for a two-for-one offer on concentrate screenwash, and then bite the bullet and mix up a big batch. You can keep it in your garage and top up every year. Problem solved.