[rob fryer]

Have just finished cleaning some new build houses the glass was covered in render also deap scratches all over the glass ,when i was cleaning the glass it felt rough even the glass which was clean and free from render. When i used my scraper it put fine scratches on the glass changed blade used light pressure on wet glass still scratched ,has anybody had same problem .
cheers rob

[Small but perfectley formed]

Yes this happens often with toughend glass try not to scrape it

[jewelcleaning]

Really?  I've used my scraper loads of times, and never left scratches?

Maybe I've been lucky and not had any toughened glass!

Jay

[Tosh]

I've read posts on this site about this very subject; I believe there's a manufacturing fault with certain types of glass which makes it really easy to scratch and it's normally the window cleaner that ends up carrying the can.

Do a search for scratched glass on this forum and also have a look at this site, which I believe (I haven't went through it) explains what you need to know:

http://www.stopscratchedglass.com/

[Ian Rochester]

I small extract from Tosh's link, which I think is very important, we are currently in dispute about scratches on a £1.3m property that we cleaned, luckily we have a signed Glass Waiver Liability sheet for the job.

Proper Training and Techniques

1.   Always keep the glass wet when scraping construction debris from the glass.

2.   Use only new razor blades or sharpened scrapers.

3.   Never move the scraper backwards on the glass. Construction debris caught behind the scraper can scratch the glass.

4.   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.

5.   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".

[rob fryer]

Thanks for the advice all,Have found a spray chemicial for removing morter from glass made by everbuild sold at buildcentre,Anybody tried  it.