Hello,
I hope that I am not correct here, but I believe that the method they use is a rubber or other flexable material, and hot stamped on the metal. This ink contains finely groung glass, that bonds to the pores of the surface that it is applied to... You might be able to heat or cool the area to be cleaned, with a hair dryer or heat gun on medium, expansion or contraction of the metal "MAY" release the ink. Use a hard wooden object with a point to test the ink, not metal. This type of ink is made to be permanent on all of its applications.
Solvents will not have the desired affect, if I am correct, as the glass particles will protect the ink under it.
Please note that I have not been able to find a photo of this printing, however the type of printing, that I have described, has been used on glass Pharmacutical glass bottles to imprint the lot and expiration date numbers, and is required by law to resisct solvents and autoclaveing, High Heat.
Hope this helps,
Bill