If you have an old table tennis paddle that is covered in glue, you can remove the glue by following these steps:
1. Use a putty knife or other sharp object to scrape off as much of the glue as possible.
2. Apply a generous amount of rubbing alcohol to a clean cloth and rub the glue-stained areas of the paddle.
3. Rinse the paddle with warm water and dry it with a clean towel.
4. Repeat steps 2-3 if necessary.
5. Once all the glue has been removed, apply a small amount of table tennis paddle wax to the paddle to protect it from future damage.