Recently, I saw my specs has scratches. So I asked my friend if it is permanent or temporary. He told that sand( silica particles) has rubbed against the silica particles of my specs, and it has caused scratches( and this is primarily how scratches are formed on specs).
And that this is permament.
But to remove the scratches, apply soap. As soap has dirt loving properties and it will cause the dirt to come out of the specs, and then wash it.
I was literally blown by this.