Advice for removing decor glued to walls

There’s a wall in my house that has some unusual decor in the form various circles of course sand adhered to the wall. I’m trying to remove them so I can repaint, but they seem pretty stuck on. By the looks of it, the previous owner made a 2-3” full circle of glue or some other adhesive and then packed sand on top. I’ve tried manual removal with a cheap drywall knife as a chisel, but it doesn’t do much. I’ve also tried some acetone to soften it up and steel brush, but no luck there either. There’s about 16 of these scattered over a 1x3’ section in the middle of the wall and I’m hoping there’s a way to remove them from the wall without damaging the drywall. Any ideas?