- Go after the joint with sandpaper or any kind of sharp tool to get rid of the excess globs of glue.
- Take a piece of dowel that's the appropriate size and wrap a piece of sandpaper around it. Use that to go into the holes in the chair legs of the chair. Twist the dowel around to sand the inside of the hole.
Use carpenter's glue in the joints, and tap the pieces back together with a wooden or rubber mallet. Clamp the pieces together and let the glue dry overnight.
If you run into a case where someone has put screws in the chair, you may have to drill into the wood to get the screw out. Then put glue on a dowel that's the about the same diameter as the hole and tap the dowel into the hole.
After the glue has set up, sand off any excess.