How to sharpen a lawnmower blade?

Steps:
1. Disconnect the spark-plug wire from the spark plug to prevent accidental starting.
2. Tip up the lawnmower with its spark plug pointing vertically.
3. Put on a leather work glove and grab hold of lawnmower blade.
4. Use ratcheting socket wrench to remove the nuts holding the blade to the mower.
5. Remove the blade from the mower.
6. Clamp blade in a vise and use a metal file to sharpen the cutting edges of the blade.
7. Chuck a blade-sharpening stone into a drill/driver and use it to sharpen the lawnmower blade. Be sure to keep the stone's plastic guide against the rear of the blade.
8. Sharpen the lawnmower blade using a bench grinder.
9. Repeat to sharpen opposite end of blade.
10. Set the sharpened blade onto a blade balancer. If the blade is out of balance, file or grind a bit more steel from the heavy end.
11. Use a putty knife to scrape away any matted grass clippings from the underside of the mowing deck.
12. Reinstall the blade, firmly tightening the nuts with a ratcheting socket wrench.
13. Lower the mower and reattach the spark-plug wire.