Dr. Wack "CW1:100" CW1:100 "Super" screenwash concentrate 250ml

CW1:100 "Super" screenwash breaks down smear film — as long as you get the dose right

What is CW1:100 "Super"? A screenwash concentrate from Dr. Wack that goes into your washer water at 1 to 100 and lifts glare and smear film off the windscreen. Developed for windscreen washer systems and headlight washers. Not an antifreeze: it doesn't lower the freezing point.

Dr. Wack CW1:100 "Super" screenwash is a concentrate for the windscreen washer system that you dilute at a ratio of 1 to 100. The 1:100 in the name isn't a model code, it's the recipe on the label. One dosing chamber holds 25 millilitres and makes 2.5 litres of ready-to-use washer fluid, so the 250 millilitre bottle makes 25 litres. That's ten dosing chambers per bottle.

The film it goes after isn't a layer of dust. Bug remains, diesel soot, silicone and wax residue build up on the glass as a milky-looking, water-repellent layer. A glass sealant is water-repellent too, but it's built up evenly — it gives you clean beading. Glare film is the opposite: it scatters incoming light instead of letting it through. You'll notice it when every oncoming car dazzles you at night, even though the wipers just went over the glass.

• The mixing ratio is in the product name. With the cap slightly unscrewed, squeeze the lower part of the bottle until the dosing chamber is full — that's the whole measuring system. That turns 250 millilitres into 25 litres of washer fluid, and the 5 litre canister into 500 litres.
• The anti-limescale formula keeps the fan jet open. It binds the lime in tap water before it can settle in the nozzle opening. In practice: what doesn't crystallise can't clog the opening either, and the spray pattern stays wide instead of lopsided. Auto Bild gave the Super full marks for material compatibility, 15 out of 15.
• In winter the dose doubles, not the frost protection. For antifreeze mixes, Dr. Wack specifies 1 to 50 — four dosing chambers or 100 millilitres per 5 litres of finished mix. The Super doesn't replace antifreeze, it boosts its cleaning power.

Detailing1's tip from the shop: What we see day-to-day: the most common mistake is tipping it into a full reservoir. If you empty the dosing chamber straight into the tank and top up with water, you're not mixing — the concentrate just sits at the bottom. The first sprays foam up over-concentrated, the last ones are almost pure water. In the product information sheet, Dr. Wack recommends mixing the components in a separate container first. Empty 2.5 litre jug, 25 millilitres in, shake, pour — then what you dosed is what reaches the nozzle.

One dosing chamber holds 25 millilitres and makes 2.5 litres

CW1:100 "Super" screenwash is dosed at 1 to 100. One dosing chamber holds 25 millilitres of concentrate, making exactly 2.5 litres of ready-to-use fluid for the washer system.

Dose by feel and you pay twice. Too little concentrate, and the smear film stays as a haze the wipers just spread around. Too much, and the surfactants foam on dry glass, leave streaks and cost you two extra sprays to clear. The dosing chamber takes the guesswork out: unscrew the cap slightly, squeeze the lower part of the bottle until the chamber is full, unscrew the cap, pour in.

The work in the washer water is done by anionic surfactants. These are molecules with one water-loving and one grease-loving end that wedge themselves between the glass and the smear film and lift the film off. For you, that means the wiper doesn't just push the dirt around anymore, it takes it with it. That's exactly why the amount decides the result, not the number of wipes.

With the 40 millilitre single-dose bottle, there's no maths at all. At 1 to 100, 40 millilitres makes 4 litres of washer water, so one dose covers about one reservoir fill on most cars. That bottle lives in the glovebox as a top-up on the road; the bigger pack handles the planned dosing at home.

That the dosing chamber holds exactly 25 millilitres is straight from the product information sheet out of Baar-Ebenhausen. One fill, two and a half litres — that's all the mental arithmetic summer dosing asks of you. In canister format, the same sum looks like this: 5 litres of concentrate make around 500 litres of washer fluid, or 250 litres at winter strength.

Dr. Wack also says the cleaner extends the life of your wiper blades. There's no way to check that, but the mechanism is plausible: a wiper blade gliding over a loosened film works with less friction than one pushing dry dirt across the glass. The bigger lever, in our view, is never running the blade dry anyway — spray first, then wipe.

From our own experience: water into the mixing container first, then the concentrate, then shake. The other way round, it foams over when you shake, and whatever ends up in the sink is missing from the tank. What sets the four screenwashes in this range apart comes down to exactly one number — the mixing ratio.

The Super boosts your antifreeze — it can't replace it

CW1:100 "Super" screenwash doesn't lower the freezing point. In winter it goes into a finished antifreeze mix on top, dosed at 1 to 50 instead of 1 to 100.

The order is in the product information sheet and still rarely followed: antifreeze concentrate first, then fresh water, then the Super. Four dosing chambers, i.e. 100 millilitres, per 5 litres of finished antifreeze mix. If you put the cleaner into the empty canister first, it only gets mixed in by chance as you fill up.

It gets expensive with antifreeze concentrates rated down to minus 60 degrees. Those must never meet the Super undiluted. Dr. Wack requires you to dilute the concentrate with fresh water to minus 30 degrees at most first, and only then add the cleaner. The sheet doesn't give a reason. We stick to it anyway, because a clogged washer jet in January is no small thing.

The reason tap water is good enough here is the anti-limescale formula. In hard-water areas, calcium is what gradually grows the fine nozzle opening shut over the years. The formula binds it before it can settle — which is why Dr. Wack specifies fresh tap water, not distilled. Day to day, that means you skip the jug from the DIY store and mix at the tap.

The second limit is in front of the windscreen. No washer fluid dissolves dried-on bug shells on the bonnet, grille and headlights, because there's no dwell time — the wiper is on the glass for seconds, not minutes. If the film builds up while you're driving, the Super is the right tool. If the remains dry on while the car is parked, you need an insect remover that clings as a gel on the surface, one that stays put instead of running off.

In issue 22 of 2022, Auto Bild put the Super up against eight other screenwashes. Result: good, grade 2.4, third place out of nine. Full marks of 15 for material compatibility, 56 out of 80 points for pure cleaning power.

Translated: if maximum cleaning power trumps everything for you, there are stronger contenders in the field. If you don't want anything to happen to paint, rubber seals or plastic headlight lenses, you're in the right place — and according to the manufacturer, the formula was developed for exactly those parts.

Dose it yourself and you stop paying for water

A 1:100 concentrate doesn't haul water around. 250 millilitres of CW1:100 "Super" screenwash become 25 litres of ready-to-use fluid; the other 24.75 litres come out of the tap at home.

Which pack pays off depends less on the car than on how you drive. If you do lots of motorway miles, you'll empty the washer reservoir much faster in bug season than the rest of the year — that's what the 250 millilitre bottle with dosing chamber is built for. The 40 millilitre single-dose bottle is the glovebox top-up. The 5 litre canister pays off from the second car in the household.

A second consumer is listed in the product information sheet and usually gets lost in the windscreen discussion: the headlight washer system. Cars with pop-out washer jets on the headlights draw from the same reservoir. That doesn't change the dosing, but it does change consumption — if you trigger the system regularly in winter, the reservoir empties much faster and you're better off with the canister than the single-dose bottle.

If you want to mix yourself and you've got a tap anyway, the concentrate is the leaner route — on the shelf, in the boot and in the amount of plastic per litre of washer fluid. If you want the canister ready-mixed in the boot because there's no water on the road, grab the ready-to-use pre-mix. That's not a ranking, it's a decision about where the water gets added.

The first time round, measuring feels more of a faff than emptying a ready-made jug. That's normal. After two or three fills you've got the hang of it, and the dosing chamber becomes what it is — the measuring cup already built into the bottle.

The tip no label gives you: don't wait for the first frost forecast to switch to winter dosing. If you move to 1 to 50 in October, while late-summer bug remains are still on the glass, you get the double dose exactly when it has the most work to do. And in January the antifreeze mix has long been sitting correctly in the reservoir, instead of being thrown together on the driveway at minus five.

How to use CW1:100 "Super" screenwash

Mix first, then fill

Take a clean container that holds at least 2.5 litres and put the water in first. Then empty the dosing chamber: unscrew the cap slightly, squeeze the lower part of the bottle until the chamber is filled with 25 millilitres, unscrew the cap, pour in. Give it a quick shake, then pour it into the washer reservoir.

The mixing ratio in summer is 1 to 100. One dosing chamber makes 2.5 litres, the 250 millilitre bottle 25 litres in total, the 5 litre canister around 500 litres. The 40 millilitre single-dose bottle makes 4 litres, covering about one reservoir fill.

For winter use there's a different number and a fixed order. Antifreeze concentrate first, then fresh water, then the cleaner at 1 to 50 — four dosing chambers or 100 millilitres per 5 litres of finished antifreeze mix. With antifreeze concentrates rated down to minus 60 degrees, first dilute with fresh water to minus 30 degrees at most, and only then add the cleaner.

If the reservoir is still half full, calculate with what's left, not the nominal volume. Two litres left plus 25 millilitres of new concentrate make a much stronger mix than intended, and that shows up as foam on dry glass. Before switching to winter, run the reservoir empty and mix fresh — that's the cleanest break between summer and winter dosing. For cleaning the bonnet and grille in between, use the insect remover that clings as a gel, not the washer system.

Notes: The concentrate isn't an antifreeze and doesn't lower the freezing point — in winter you still need antifreeze; the cleaner only boosts its cleaning power. The formula was developed for windscreen and headlight washer systems, including plastic headlight lenses and fan jets. Dried-on bug remains on the front end need a product with dwell time, not washer fluid. Store the bottle closed and frost-free so the dosing chamber doesn't gum up, and close the canister tightly again after use.