Asia-Pacific ยท Glass Manufacturer
AGC Inc. โ Window Cleaning Guide
๐ฏ๐ต Japan ยท Last reviewed by Justin Orloff
Quick Facts
founded
1907
hq
Tokyo, Japan
primaryMaterials
Flat glass - float, tempered, laminated, coated
glazingPartner
Glass supplier to all major window system manufacturers
marketTier
Mass Market to Premium (glass manufacturer)
Brand at a Glance
- Country: Japan
- Founded: 1907 (as Asahi Glass)
- Global position: One of the world's largest flat glass manufacturers
- Key product brands: Planibel, Stopray, Mirastar, Sunergy
- Glass types: Float glass, tempered, laminated, coated glass, self-cleaning glass
- Market: Architectural glass globally - residential, commercial, automotive
- Website: agc.com
Product Range
- Planibel
- Stopray
- Sunergy
- Mirastar
- Thermobel
Why This System
AGC's most important product for window cleaners is Mirastar - the self-cleaning glass with a photocatalytic titanium dioxide coating on the outer surface. This coating is on the face you clean. It is not a standard glass surface. Mirastar degrades dirt through UV reaction and rinses clean with rain. But it must never be touched with abrasive pads or cream cleaners, and it must never be treated with water-repellent or glass sealant products - these block the photocatalytic reaction. AGC's Stopray and Sunergy solar control coatings are on the inner glass surfaces within the insulated unit and are not accessible for cleaning. However, cleaning chemistry that compromises the edge seal of the unit can allow moisture into the cavity - where these coatings then degrade. pH-neutral cleaning at the glass edge is not optional. Japan's UV loading and humidity make coating integrity a live issue. AGC glass in southern Japanese prefectures and on exposed coastal elevations has a shorter coating service life than the same glass in northern or sheltered positions.
Step 1 of 2: Manufacturer Recommendations
Official Care Guidance
Step 2 of 2: The Orloffs Protocol
The Orloffs Protocol
Since 1999 I've cleaned hundreds, if not thousands, of different window brands and systems. The physics of clean glass don't change from one brand to the next. Follow the steps below and you'll clean your AGC Inc. windows to a professional standard โ guaranteed.
Pro Tools
My daily tool list. This is what I carry to every job.
Follow these steps in order. Each one builds on the last. This is the same sequence I use on every AGC Inc. installation.
- 1
Preparation -- before any water touches the glass
Fill the bucket with at least 10 litres of water. Add soap for cleaning power -- enough to cut through environmental deposits, not so much you are fighting foam.
Before touching the glass, brush down the surface to remove loose dust, spiderwebs, and debris. Any grit left on the glass during the wash phase risks scratching during agitation.
Check the glass frame condition before you start. Confirm which cleaning product is safe for that surface before opening any bottle.
Cover anything below the windows that cannot be moved.
- 2
Agitation -- apply and work the solution
Dip the microfiber T-bar completely into the soap water, both sides. Remove excess water with your hand so it does not drip. Apply the solution across the entire glass surface with overlapping passes.
The goal is to fully dissolve and release every deposit from the glass surface. Anything not released during agitation gets transported across the glass by the squeegee as a smear.
For stubborn spots -- insect marks, salt residue, environmental deposits -- re-apply soap water and allow it to soak for a full minute before agitating again. Use more soap water, not more pressure.
For panels above arm reach: attach the T-bar to an extension pole. Work in sections -- top first, then middle, then bottom -- keeping each section wet until you squeegee it.
Rinse the T-bar cover regularly during the job. A dirty applicator causes microscopic scratches that accumulate over time.
- 3
Detail the frame edge before squeegeeing
Use your 100% cotton towelling rag, finger pressed into the fabric, to work into every junction and remove pooled soap water before the squeegee pass.
This prevents drips running down onto already-cleaned areas during squeegeeing and keeps soap water out of drainage channels.
On AGC Japan glass frames, pay particular attention to the bottom edge where glass meets the frame sill -- water pooled here runs into drainage openings and leaves residue over time.
- 4
The squeegee
Tilt the squeegee at a slight angle so soap water spills from one side of the channel only -- not both. If the rubber is jumping or squeaking, either the rubber is not lubricated enough or the glass surface has warmed.
Cutting in: start with the rubber blade making first contact on a dry edge of the glass.
Side to side: horizontal passes across the panel. Works well on wide sections. Top to bottom: vertical passes down the panel. Works well on tall narrow sections.
The J tune: one smooth unbroken motion top to bottom, wrist rotating at each end to reverse without lifting the rubber. The most efficient method on larger panels -- but it requires training before applying it to premium glass.
Wipe the rubber dry after every pass. Overlap each stroke by 2-3 cm.
- 5
Final edge detailing
After squeegeeing, there is always a residual line of water along the bottom edge and at the panel sides. Take a dry cotton rag, fold to a clean corner, and detail these edges in one smooth pass.
On AGC Japan frames, the bottom edge where glass meets the sill requires the most careful attention. Water left here runs into drainage and leaves residue that affects the next clean.
Rotate the rag to a clean section after every pass. If the rag picks up grit at any point, replace it immediately.
- 6
Frame wipe and hardware check
On glass from AGC Japan: use pH-neutral solution only on all coated surfaces. Any coating damage -- Low-E, self-cleaning, solar control -- is permanent and the unit must be replaced.
Check that all drainage openings are clear and unobstructed. Water must be able to flow freely -- a blocked channel leads to accumulation that affects seal performance over time.
Operate every opening window through its full range. Stiff handles or resistance at locking points indicate hardware that needs lubrication. Flag it to the owner rather than forcing it.
Pro Tips
- When in doubt about whether a glass is Mirastar, treat it as Mirastar - the Mirastar protocol (no abrasives, no sealants, pH-neutral or pure water only) is safe on all glass types
- Pure water fed pole rinsing is the ideal maintenance approach for Mirastar glass - it achieves what the self-cleaning coating is designed to do without any risk of coating contact from squeegee rubber or cloth
- After a Saharan dust event in Japan (kosa season, typically March to May), Mirastar glass may carry a yellow-orange mineral deposit. This mineral is alkaline - pre-rinse with plenty of pure water before any cleaning to float it off rather than grinding it in
What NOT To Do
- Do not use abrasive pads on any AGC coated glass surface
- Do not apply hydrophobic glass sealant or water repellent to Mirastar self-cleaning glass
- Do not use acidic or alkaline cleaners at the glass-to-frame edge seal junction
- Do not use cream cleaners on Mirastar - they leave a hydrophobic residue that blocks the photocatalytic coating
- Do not use metal scraper blades on coated glass surfaces
Bundle Kits and Tool Recommendations
Bundle Kit
Cleaning Frequency
Clean every 4โ8 weeks depending on environment.
Frequently Asked Questions
Field Notes
โMirastar self-cleaning glass does not mean no cleaning is needed. It means the glass requires less frequent cleaning and the outer surface breaks down organic deposits faster than standard glass. But city pollution, bird contamination, and mineral deposit still accumulate and still need attention - just at a lower frequency. AGC glass etching on the edge of the unit identifies the glass type and sometimes the coating specification. If the building has specification documents, the AGC product name will identify the coating tier. In Japan's summer humidity, standard AGC insulated units can show exterior surface condensation on very humid mornings - this is the unit working correctly, not a seal failure. It clears as morning temperatures rise.โ
Justin Orloff
What's next for you?
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