Scrape and cut out any lose particle board using a utility knife.
Remove oils and other debris from the damaged area by sanding it with a fine-grit sandpaper.
Fill cracks and depressions using a wood fill that matches the shade of the top. Use a putty knife at a low angle to the surface to spread the wood fill into the damaged area and at more of an angle to remove excess fill. Press the wood fill into the cracks and depressions and smooth it out as best as you can. Allow the wood fill to dry according to the directions.
Sand the repaired area lightly using a fine-grit sandpaper. Apply a second coat of wood fill to correct for any shrinkage. Sand the second coat after it dries.