The slag will come off...the little divit that it leaves behind will be there for future generations.
You can use a razer blade to scrap to off but you still will have little pot holes in the glass It will feel a little smoother
Thank god it's only the tiny rear window of my 65 Impala 2dr ht. I had to re allign the rear qtr some when I replaced it. It didn't quite line up. I thought if it was inside the car [ down] it would be OK. I was working in the door jam area and F'd it up.
I've used a razor blade too, with good results. I know they are there but nobody else seems to mind, I've never had anybody even comment on the divots.
I'LL give that a go, its a whole bunch of teeny tiny little specks. See how that looks , if not I suppose I can look for one that isn't messed up.
I have used gel-type super glue (yeah, I fucked up, once!) Let it cure then use the edge of a fresh blade to level it. then a bit of glass polish.
It bonds with glass pretty well. If you hang out in antique shops you will see lamps with "slag glass" shades. That is made by taking the slag off molten iron and mixing it with the glass. (fun facts to know and tell)
All that said, look into furniture finish polishing grade sand paper like say 1200 grit to start with, gently remove the slag divot and very gently wet sand the glass smooth using whatever very smooth sandpaper you test with. 1st, test say, a 1000, then 1200 then on up in steps until it is smooth and clear. I watched my Buddy do high end dinning room table top "finish smooth down's" to remove scratches and such doing this AND it takes a long time to do SO I figure glass will take a longer time but it should work for you. I polished my '67 Camaro's two dash "cones" using toothpaste years ago, took at least an hour to remove haze and this was on plastic. pdq67
I had some really bad scratches on a windshield and purchased the 20 buck polishing kit from Eastwood and it took them out, took a lot of work but it did work don't know how bad your pits are but I had about 64th of an in gouges...