We’ve seen various hacks with people suggesting you can make your own car screenwash to keep your windscreen clean and save money. Here we look at whether that makes sense and how to buy screenwash and save money.
Don’t follow any recipes with washing up liquid in
One recipe we found suggests mixing water with washing up liquid and ammonia. Just no. While there’s no doubting that it might clean your screen, washing up liquid has salt in it and ammonia is a harsh chemical that can dry out rubber and plastic seals.
Think about it this way: would you use car screen cleaner to wash your dirty dishes up in? Thought not.
What does screenwash contain?
Various chemicals to make it smell nice and ensure it washes hard-to-shift stuff off your screen. This can include perfumes, butyl glycol and ethanol plus various other components depending on the manufacturer.
What about diluting glass cleaner?
Commercial glass cleaner – the sort you use on windows in the house – is not great for using in cars. The reason is as above: it contains ammonia which isn’t great for any plastic or rubber it comes into contact with.
Can you just use water?
You can, yes. But screenwash has two properties that make it worth paying for. First it has components designed to shift stubborn dirt such as dead bugs. And it has anti-freeze in it to ensure it doesn’t ice up when the weather’s cold.
If you do make screenwash, ensure it doesn’t freeze
Whatever you use, you need to ensure the solution doesn’t freeze inside the car in very low temperatures. To do this, you need to lower its freezing point. You can do that by adding what’s known as rubbing alcohol or isopropyl to whatever mixture you make.
What about using bleach?
No, it will damage paintwork. Again, would you use screenwash to clean your toilet?
Think about the water you use
If you live in a hard water area, your water will have calcium in it which leaves deposits. Think of what your kettle looks like inside. You definitely don’t want that calcium inside you car’s screen wash tank as the chalky bits could block the pipework.
We’d suggest using distilled water which has the minerals and salts removed from it.
The ingredients will cost more than actual car screenwash
We’ve seen numerous recipes for your own car screenwash. One was suggesting using white wine vinegar which last time we checked was quite pricey. Another says you can use lemon juice, which is again, expensive. Yet another suggested using some weight-lifting chalk, a hassle to buy. Some even said you could use vodka. Sacrilege, not to mention costly.
What’s wrong with screenwash?
We think it makes sense to use traditional screenwash. For a start it’s very cheap. You can buy a five litre container of concentrate that will make 25 litres of screenwash for £5.
So it’s not expensive and you know it’s been made to a particular job. Car screenwash might contain methanol which is a poisonous chemical. But if you do buy it, you know you’re getting something that’s fit for purpose.
Buy concentrate rather than ready mixed
If you go to a motor retailer (rather than a service station), you frequently have a choice between ready mixed screenwash and concentrated. Both come in five litre bottles. However, concentrate – meaning that you mix your own – can be up to five times cheaper than ready mixed.
The only thing with concentrate is that you need to have a bottle to mix it in. But everyone’s got a spare plastic bottle hanging around somewhere.
I’ve been writing about cars and motoring for more than 25 years. My career started on a long-departed classic car weekly magazine called AutoClassic. I’ve since pitched up at Autosport, Auto Express, the News of the World, Sunday Times and most recently the Daily Telegraph. When I’m not writing about cars and motoring, I’m probably doing some kind of sport or working in my garden.