Hey all! This is my first instructable, so please, take it easy on me. :) now I'll teach you how to sharpen a knife! (Rather crudely)
Step 1: Materials!
You will need:
1. A knife or blade in need of minor sharpening.
2. A coffee cup!
Step 2: Turn It Upside Down!
Take your coffee cup, and flip it upside down.
Step 3: Sharpening
Now, take the knife at a 20 degree angle to the coffee cup, sharp side facing away from you. Give it some force down, but not too much. You don't want to break the blade. Now pull the knife towards yourself. Now flip the blade over and do the other side. (Make sure you firmly hold the coffee cup. I was taking a picture the hand I usually hold it with.)
Step 4: How It Works
The bottom of the coffee cup acts as a grindstone, due to the coarse materials. When pulling the blade towards yourself (blade facing away, mind you), it cause the blade to slowly grind down. (Sharpening.)
Step 5: Warning!
The bottom of the mug will collect a metallic or steel dust. It will wash off, but it will also get on your hands. So make sure to clean up well after sharpening!
The mug should also not be used in a microwave, lest it cause damage to either the mug or the user. (Credit: jmwells)
You can also use AJAX cleaner to clean the mug. It will come off quite nicely. (Credit: Phil B)
Step 6: Finished!
Now you can use your blade to its full potential! :)