How to clean external venetian blinds: 5 methods without taking them down

If you live in Switzerland, you almost certainly have them: the external metal slat blinds known as Lamellenstoren or stores à lamelles. They are practical for shade and privacy, but after a summer they are covered in dust, pollen, spider webs and insects. October is the classic time to clean venetian blinds on the outside, before autumn rain turns the dust into grey streaks and winter makes the job unpleasant.

The good news: you do not need to take them down. Here are five methods that work in place – and the safety rules that matter more than any cleaning trick.

Why external venetian blinds get so dirty

The slats are outside in all weather. Rain, road dust, pollen and soot settle on the upper surfaces, while the underside collects spider webs and insects. In flats near busy roads or railway lines, a greasy grey film builds up quickly.

The blinds are also a checkpoint at every handover inspection in Switzerland. Our separate guide explains the rules about cleaning blinds as a tenant – this article focuses on the practical technique.

Before you start: preparation and safety

1. Check the weather: a dry, overcast day without strong wind is ideal.
2. Lower the blinds completely and turn the slats to the horizontal position.
3. Put a towel on the window sill inside to catch drips.
4. Prepare a bucket of lukewarm water with a few drops of washing-up liquid, two microfibre cloths, a soft brush and a spray bottle with clear water.

1. Dry dusting: the essential first step

Most dirt on blinds is loose dust. Removing it dry avoids smearing.

• Use a soft brush, a lambswool duster or a special slat brush that cleans several slats at once.
• Work from top to bottom, first on the upper side of the slats.
• Turn the slats slightly and repeat on the underside.
• For heavy dust, a vacuum cleaner with a soft brush attachment works well – hold the slats steady with your other hand.

2. The microfibre glove method

A microfibre glove is the most efficient tool for wiping slats by hand, because you can clean the top and bottom of each slat in one movement.

1. Put on a rubber glove and pull a microfibre glove over it.
2. Dip it in the soapy water and wring it out well.
3. Grip each slat gently between thumb and fingers and slide along it from one end to the other.
4. Rinse the glove frequently and change the water when it turns grey.

This method takes time, but it is the most thorough without dismantling.

3. Spray and wipe for light soiling

If the blinds are only lightly dirty, a quicker method works:

1. Spray a mild solution of water and washing-up liquid onto a section of slats.
2. Leave for a minute.
3. Wipe with a microfibre cloth, holding the slat from below.
4. Spray lightly with clear water and wipe dry.

Avoid spraying directly into the upper box, guide rails or motor housing of electric blinds.

4. Guide rails and cords

The guide rails at the sides and the lifting cords or tapes are often overlooked.

• Brush out the guide rails with a narrow brush or old toothbrush to remove leaves, insects and grit.
• Wipe the rails with a damp cloth.
• Wipe the lifting tapes gently with a barely damp cloth – do not pull on them.
• Do not oil or grease the mechanism yourself; if the blinds run stiffly or make noises, inform your property management.

5. Stubborn marks, bird droppings and soot

For specific stains, treat locally instead of scrubbing the whole blind.

• Bird droppings: Soften with a damp cloth for a few minutes, then wipe off. Wear gloves.
• Greasy soot film: A slightly stronger washing-up liquid solution; rinse well.
• Spider webs and egg sacs: Remove dry with a brush before wet cleaning.

Avoid abrasive sponges, solvents, acids and alkaline cleaners – they can damage the coating on the slats. Always test a new product on one slat first.

How often should you clean them?

For most flats, cleaning venetian blinds once or twice a year is enough – typically in spring and autumn. Near busy roads or construction sites, more often. Before a handover, always.

Common mistakes with venetian blinds

• Using a high-pressure cleaner: Water gets into the mechanism and can bend slats.
• Cleaning in strong sun: Soapy water dries on the slats and leaves marks.
• Pulling on slats or tapes: Slats can bend and tapes can come out of their guides.
• Leaning out of the window: No blind is worth a fall.
• Operating electric blinds while cleaning: Keep them switched off to avoid pinched fingers.

Priority Clean editorial teamOur cleaning team from Alberswil, Canton of Lucerne, shares hands-on experience from move-out, house, office and window cleaning across Central and Northwestern Switzerland.