For cheapskates only.

[Woodznutz]

You can sharpen utility knife blades easily using these sharpeners. A few swipes with the carbide sharpener, and finish with a fine whetstone and a few strokes on a steel and it's as good as new.

 

[HereWeGoAgain]

There's a type of lightbulb that are usually used in large building like factories and shops.
Inside they have a ceramic rod about 6 inches long and about 3/8 of an inch in diameter.
The rods are great for sharpening knives.