Has anyone ever used one of these before? My Grandad saw an advert in the mail and thought it might come in useful but i can work out how it can work with all colours?

Surely itll just be a clear laquer, cant see it being anything else but happy to be proven wrong.
Ray

I remember something about old polishes "melting" the paint slightly so it would spread a little and cover the scratch. T-cut alledgedly does this kind of thing then you must have to stand and twirl on it because it doesn't work!

some of these things are like silicon and just "wet" the scratch so it appears a lot darker and not as noticable but it doesn't actually do anything more. T-cut just removes the paint past the scratch like fine sanding and can't be used on the same area too much

I have an airbrush for painting models and just spray scratches with that as it only covers about 15mm wide without messing up any other paint. Rattle cans are the right viscosity for it too, just spray the can into the jar

Some vile little scrote keyed my wifes old Octavia a couple of years ago. It simply wasn't worth shelling out for a respray so I used one of the "chip stick" things that you get with a bottle of coloured T-cut and to my amazement it actually worked very well. The scratch wasn't exactly invisible afterwards, but hid it well enough that you'd actually have to look fairly closely to see it.