Got a loosen guitar button. Pull it out and clear the hole
Make some chips out of the wooden chopstick using the utility knife
Sharpen the wooden chopstick to make a post for putting it in the hole later
Fill the hole using the wooden chips
Fill the white glue in the hole and put the wooden post in. You can lightly hammer the post using handle or utility knife or scree driver to make better contact with the hole
Cut the excessive part approximately using the scissor. The remaining part above will be sanded.
Sanding preparation: Apply the tape around the post to protect the guitar finish from sanding
Sand out the remaining excessive part of the post. The picture is taken after sanding.
Remove the tape and clear the dust. Reattach the strap button and the screw back. Done!