Detecting a worn out burner worm

When the worm gets sharp edges it starts grinding coal in the pot. The sharp edge of the worm is almost sharp enough to cut skin. This area of the worm would be located at the bottom of the pot, just below the bottom of the burner plates You may also notice a dark spot in the pot that isn't always in the same place. Notice also that the worm bushing is very worn out. This worm is 20+ years in use.

Both should be checked on the yearly maintenance cleaning aswell as to check the water coil gasket area for leaks tighten up the bolts