While it will certainly remove the tarnish, many toothpaste products contain micro-abrasives that can etch the surface of the metal.
There are a few materials you'll need to etch on glass both successfully and safely.
If you have anti-reflective coating on your lens, remove scratches with Armour Etch.
While attending to the girl, the doctor reported watching the words "Esther Cox you are mine to kill" etch itself into the wall plaster by unseen hands.
However, most are hand engraved as single picks or in small batches using a laser engraver to etch the surface of the metal with the desired design.
Acid - Corrosive acids such as hydroflouric acid are carefully spotted on the surface just long enough to etch the design and are then washed off.
With etchings, this company uses a sandblaster to actual etch your chosen label into the bottle and then paint it in the colors of your choosing.
A quartz counter doesn't require any of this; it doesn't stain, scratch or etch.
The acid used to etch the surface has darkened the parts richest in copper, while those richest in tin remained white.
In fact the uniformity of brass and bell-metal is only superficial; if we adopt the methods described in the article Metallography, and if, after polishing a plane face on a bit of gun-metal, we etch away the surface layer and examine the new surface with a lens or a microscope, we find a complex pattern of at least two materials.