I'm guilty of using material in my projects that many would consider too full of defects to use. I'm especially fond of salvaged Ponderosa pine. Pulled from warehouses destined to be razed it's saved, cleaned up, and resold. I think it looks great.
Unfortunately, the wood sometimes has knots that are on the verge of falling out. I guess I could try cutting around the knots to eliminate them, but I'd waste too much material. Plus, I love the look of intact knots in the finished project. Thankfully, cyanoacrylate (CA) glue saves the day.
Thin CA glue is about the consistency of water, and it's the perfect choice for saving the character in this piece. Dribble the glue around the edge of the knot, allowing it to seep in and run down alongside it. Stop when the glue is "backing up" and starting to flood the surface.
Let the glue dry (which happens VERY fast), and you can run a sander over the top of the knot to remove the excess glue. In minutes you're ready to work with the piece and be confident the knots will stay put.