windows scratched and no reason why.

Hi All, need some help.

Cleaned my own windows over the weekend, just a quick going over, nothing to special, but noticed 3 of my windows scratched, and all different windows, my kit was all clean and checked as had a couple of tough first cleans back end of last week, i just did the windows and not frames, as i do my own every couple of weeks

I used the gardiner ultimate 26cm medium soft mixed brush, which is my go to brush. 

its starting to look a tatty around the edges but wouldnt put it down to that, my brush didnt touch a wall and was not placed on the ground, never really has. 

I just to get it, 

Glass does scratch and its just one of those things. Are you sure they are fresh because usually they are there and you have just noticed them now?

Hi, Could be a possibility, ive just brought myself the unger stingray and im practising on my inside so i am looking at the glass more closely than i normally would, and im hoping that the case, 

They were probably scratched previously as has been said. 

  I liked a comment from someone one here before: "If you can't scratch your hand on the brush, you can't scratch the glass".  Unless there is something sharp stuck in it of course.