How to Clean Finstral Windows: A Professional Guide
Finstral has been building windows in South Tyrol, Italy since 1969. Today it is Europe's most-certified window manufacturer, with 14 production facilities across the continent and more than 1.3 billion possible window combinations. Their PVC, aluminium, and wood-aluminium ranges are in homes and buildings across Austria, Germany, and 14 countries worldwide.
With 25 years of professional glass care, I know what these windows need to stay crystal clear. This guide covers Finstral's official care recommendations alongside the professional technique I use when I clean them.
Why Finstral Windows Need Careful Technique
Before we get into the cleaning method, it helps to know what makes Finstral different from a standard window. This shapes every decision you make.
Multiple materials, one window. Finstral produces four distinct ranges: PVC (FIN-Window), PVC with aluminium exterior cladding, full aluminium (FIN-Project), and wood-aluminium (FIN-Ligna). Each material responds differently. What is safe on glass and PVC can damage an aluminium coating. Knowing which Finstral range you own matters before you start.
Precision-coated surfaces. Finstral offers over 200 surface finishes across its aluminium ranges. These coated surfaces are built to last, but they need soft cloths and mild products. Abrasives and solvents degrade the coating over time.
Engineered seals and drainage. Finstral windows feature rubber gaskets, precision fittings, and integrated drainage channels. These components are built to close tolerances. Sharp tools, chemical cleaners, and high-pressure water near these parts cause premature wear.
Before getting into Finstral's official care advice, it helps to understand the foundational glass-cleaning technique. The same professional method works on any premium window. If you are new to it, the Window Cleaning Manifesto is free and takes five minutes.
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What Finstral Recommends
These guidelines come directly from Finstral's operating and safety instructions. Their full manuals are available at finstral.com/manuals.
- For glass, use lukewarm water with mild washing-up liquid and a soft cloth.
- For all frame surfaces, use mild soapy water and a soft cloth. This applies to PVC, aluminium-clad, and wood-aluminium exteriors.
- Do not use aggressive or solvent-based cleaning agents on any surface.
- Do not use ammonia-based products on aluminium-clad or PVC-aluminium windows.
- Do not use sharp-edged objects or abrasive materials on the glass, frames, or fittings.
- For insect screens and nets: vacuum the dust first or wipe with lukewarm water and a soft cloth. No solvents. No ammonia. No hydrocarbons. Allow the net to dry completely before rolling it up.
- For hardware and the fanlight tilt mechanism: inspect and lubricate at least once per year. Finstral recommends that qualified personnel carry out this work. Contact your installation company if you are unsure.
These guidelines protect the materials. My job is to add the glass-cleaning technique on top of them. That is where 25 years of professional experience counts.
The Professional Technique for Finstral Glass
What You Need
These are the tools I use every day. Have everything within reach before you start.
- A T-bar applicator with a microfiber cover (a T-shaped handle with a horizontal bar covered in microfiber fabric, designed to wash glass)
- A professional squeegee with a fresh rubber blade (a flat tool with a rubber blade that shaves the water off the glass)
- A bucket with lukewarm water and one drop of mild dish soap per litre
- 100% cotton towelling rags (dry rags for detailing the edges)
- A soft cloth for the frame surfaces
Do not use paper towels on the glass. They leave fibres behind and have no place in professional glass work.
Detail the Frame First
This is the step most people skip. And it is the step that causes most streaks.
Before touching the glass, wipe down the window frame edges with a cloth dampened in mild soapy water. This removes the dust, pollen, and grime sitting on the frame. When you run the squeegee across the glass, the rubber edge makes contact with the frame. If there is dirt on that frame, the squeegee picks it up and drags it across the clean glass as a streak.
Clean the frame first. Every time.
For Finstral aluminium-clad frames, use a soft cloth only. No abrasive cloths, no stiff brushes.
Agitation: The Step That Changes Everything
Dip your T-bar applicator completely into the soapy water on both sides. Apply the solution across the whole glass area using up-and-down or side-to-side motions. The idea is to dissolve the dirt, ready for the squeegee to shave away.
If the dirt isn't fully dissolved in the soap water and released from the glass, the remaining dirt still stuck will be transported over the squeegee, leaving smudges or smears.
Take your time with this step. On large Finstral aluminium panels, cover the whole surface with overlapping strokes. Do not rush to the squeegee.
For stubborn spots like insect marks, re-apply and agitate again. Never use a razor blade or sharp object on Finstral glass.
Detail the Frame Again Before Squeegeeing
Once the glass is agitated, run a dry corner of your cotton rag along the top edge and both side edges. This removes the pooled soap water sitting on the frame edges. When the squeegee reaches those edges, it will not pick up dirty residue and drag it back across the glass.
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The Three Squeegee Turns
There are three professional squeegee turns. Mastering each one and combining them is what produces consistent, streak-free results.
Side to side. Start at the very top edge of the window with a dry rubber. Work across the glass in a straight horizontal line. Tilt the squeegee at a slight angle so the soap water spills from only one side of the channel. Wipe the rubber dry after each line. Overlap slightly into the next line down. Repeat until the window is complete.
Top to bottom. The same steps as side to side, but working down the glass in vertical lines. Start in the top corner with a dry rubber. Tilt to direct water to the lower side. Wipe the rubber dry after each line. Overlap into the next line across. Repeat to the bottom.
Turn with a twist (the J tune). This is the professional continuous motion. From the top of the window to the bottom is one endless, smooth movement. There are no stops. Your thumb is your guide: as you reach the end of a horizontal pass, rotate your wrist so the squeegee turns and continues down. At the bottom, rotate back and return across. When you have this in your muscle memory, it is the fastest and most consistent turn for any window size.
On large Finstral panels where you cannot reach the top, use the top-to-bottom turn with a pole first until arm height, then finish the lower section with the side-to-side turn.
Finishing: Edge Detailing
After squeegeeing, there is always a thin line of water along the bottom edge and at the sides where the squeegee cannot close out completely. Take a dry cotton rag, fold it to a clean corner, and detail these edges in one smooth pass.
Get your finger into the edge where the glass meets the frame seal. Remove any pooled soap water sitting there. If this is left to dry, it leaves a residue mark that shows up as soon as the sun hits the glass.
Rotate the rag so you are only ever touching the glass with a clean, dry section. Replace the rag with a fresh one every few windows.
The Insect Screen Net
Clean the net separately. Vacuum the dust off first. Then wipe with a cloth dampened in lukewarm water. No solvents. No ammonia. Allow the net to dry completely before rolling it back into the cassette. A damp net rolled into a sealed cassette causes mould buildup inside the housing.
How Often Should You Clean Finstral Windows?
Twice per year is the minimum for most homes: once in spring, once in autumn. In Vienna's urban environment, with traffic pollution, pollen, and construction dust, I recommend quarterly cleaning to keep the glass performing at its best.
For Finstral aluminium-clad frames, a twice-yearly wipe-down with mild soapy water removes the acid rain deposits and pollution grime that accumulate on exterior surfaces.
Hardware inspection and lubrication: at least once per year. Contact your Finstral installer or dealer.
What NOT to Do With Finstral Windows
Finstral is specific in its care instructions about what to avoid. These are not suggestions.
- No solvent-based cleaning products on any surface.
- No ammonia-based window sprays. This rules out most commercial glass cleaners.
- No abrasive cloths, steel wool, or stiff brushes.
- No sharp-edged tools near the glass or frame.
- No high-pressure water directed at the frame joints, drainage channels, or hardware.
- No rolling up a damp insect screen net.
Protecting Your Investment
Finstral windows are built to last decades. The glass stays crystal clear, the frames hold their finish, the seals stay tight, and the hardware operates smoothly, when the cleaning technique is right.
In over 25 years of cleaning premium glass across Vienna and Melbourne, I have seen the difference between windows that age well and windows that do not. It comes down to technique and consistency, not expensive products.
Finstral's care guidelines give you the product rules. The professional technique in this guide gives you the method. Together, those two things protect everything the engineering was designed to deliver.
If you want to take the technique further, the Window Cleaning Manifesto is free at orloffs.com/manifesto. For the complete training system with AR tool, step-by-step video, and lifetime access, the full programme is $69 at orloffs.com/for-home-owners. Less than one professional cleaning visit pays for it.
About the Author
Justin Orloff is a professional window cleaner with 25+ years of experience. He has cleaned windows across Vienna and Melbourne, from private homes with premium architectural glass to commercial facades and high-rise buildings. He created the world's first AR window-cleaning training platform.
