I've got (what I believe is) the original rear glass for my '70. I intend to tint the windows all around, but I would like to remove the greenish tint from this rear glass first. Is that possible or is the tint made into the glass? I've watched several tutorials on removing old tint so I'm ready for the grunt work, but I didn't want to go scraping away at the glass if it's a pigment mixed into the glass itself. Is that a thing? Thanks in advance.