I would suggest Scorch's plan
A couple of things. The O.P's stock looks like a low grade piece of wood that was stained and then finished with something semi clear. Obviously it could have been finished with a one step stain/finish. Stain to make it dark like higher grade walnut.
Refinishing, that will at least look good, can only be done after the stock has been taken down to bare wood and the marks eliminated during the overall sanding. If you simply sand, scrape, or try to wash out the ink with some sort of concoction and put some finish over everything, nothing will match. The ink ugliness will turn into something bigger and more noticeable. Short of very dark staining that part of the stock will never look like the rest of the stock.
There are exceptions for damage repair. If you know what the original finish was. I.e., Oil, spar varnish, wax, etc. It's possible to do a small repair to be un noticeable.
As far as glass scrapers, that's a new one on me and I'm 73. I have all of my grandfathers high carbon steel scrapers. Some have various radius curves, some look like they were made from worn out hand plane blades with the edge turned to scrape. Made and used prior to sand paper and electric powered hand tools. All of the finish carpenters that had their apples together to skillfully use them are long dead. I use them only to get the old finish off of something. Then I cheat with sandpaper. Usually with sandpaper attached something that plugs into power.