Removing glue residue

So this sort of ding to the paper is very common when removing stickers. I would gently scrape the edges to make them blend in better if possible. Rubbing the area through some wax paper may help flatten it down. Filling in the gap would be very difficult to match and blend so just make the best of it.

I have found that adhesives vary widely as to what will help remove them. It could just be that the crepe eraser will work on a slightly different adhesive.  Crepe erasers have their place for sure but it is a limited place. When I have used them I have had to keep a clean bit of cardboard nearby to roll the adhesive onto it. It is a messy business.

That makes sense.  I followed the hairdryer steps in your "Remove Tape with Heat" video, and the heat did help loosen the tape.  Thanks for that tip!  You mention several methods for removing adhesive, including using solvents.  Although I was working on a modern dust jacket, my fear was that using solvents could be too harsh.  Is something like isopropyl alcohol safe to use without mucking up the cover?

I also watched a video on your YouTube channel "Remove Library Bar Code Sticker" to do just that, but accidentally nicked (gouged?) the inside of the inside back of the hard cover.  Do you have a video or advice on a quick remedy for this?