-for this I have used Gimp2.8 and G’MIC 1.7
1.Create a new image at 1024px by 1024px.
2.Filters -> Render -> Clouds -> Plasma with Turbulence 5.0
3.Filters -> G’MIC -> Black & White -> Hard sketch with following settings
Done! Play around with different starting textures and filter settings, you can make a wide variety of scratches.
Result:
Can you maybe show some examples ?
The inserted images are not showing like the link is broke.
very sorry,i have attached the images again.current attachment method is messy - i tried to avoid repetition of images inline and as attachment but couldn’t.
if you want a sketched effect to the scratches,use Solid Noise or Turbulence applied to a layer as displacement map(Filters -Map - Displace).
Helpful and useful !
Thanks , nice tip and thanks for the examples 
