How do I remove wallpaper glue that was painted over with primer?
Many months ago we removed old wallpaper using Dif and a lot of elbow grease. The walls looked pretty good. Yesterday I painted one wall with primer to see if I would notice any glue. Unfortunately, I could see that there was lots of glue still on the wall (now under the primer). Does anyone know how to fix this? How do I remove the glue now that it has a coat of primer over it? Thank you!

leave it dry and drag a razor blade scraper across it. Not scrape but drag with force but not too much that you damage the drywall then use some "Behr new drywall" primer heavily over the area.