There are many commonly held ideas about what is, and what is not, safe to use to clean windows. Unfortunately, many of these ideas are not valid. Below is a list of the most commonly spread falsehoods about glass scratches.
Window cleaning scrapers scratch glass.
If used properly, a scraper will not scratch glass. This includes any size or style of metal scraper. A nick in a scraper will scratch glass. This is also incorrect. Aside from leaving sections of the glass inadequately cleaned, and nick in the scraper with not adversely affect the glass.
Steel wool will scratch glass.
This is also false. Experimentation has shown repeatedly that #0000 steel wool with not scratch the glass surface.
THE FACTS
With some of the myths exposed, what are some facts about construction window cleaning?
Construction window cleaning carries a very high risk of glass damage if excess construction debris is present or if the window cleaner is not properly trained. Here is a list of what can cause scratches.
Construction debris
Construction debris behind a scraper, or rust on a scraper
Construction debris or rust in steel wool
Construction debris in a strip washer
Fabricating debris fused to the surface of low-quality tempered glass during the tempering process.
PROPER TRAINING AND TECHNIQUES
Given the magnitude of the challenges faced in construction window cleaning it is clear that proper training and techniques are vital to minimizing the amount and severity of glass scratches. Listed below are some basics of construction window cleaning that, when followed, can greatly reduce scratches. For a more detailed discussion of this topic, refer to the article titled Constuction Window Cleaning Basics.
Always keep the glass wet when scraping construction debris from the glass
Use only new razor blades or sharpened scrapers
Never move the scraper backwards on the glass. Construction debris caught behind the scraper can scratch the glass.
Notify the project manager at the first sign of excessive construction debris on the glass. The offending party should be held responsible for any extra cost or liability for removing the construction debris.
Get scratched glass waiver signed for all tempered glass prior to starting any window cleaning. For example, "(Your company name) will not be liable for any scratches on any tempered glass".