Firewood

There are a lot of DC and AC-powered saw sharpeners available, and they seem nice, but I didn't want to buy one.  Mainly because I can bring a chain into the local shop and they will sharpen it for about $6.  And for $6, you walk out with a chain that is "like new."  However, they can only sharpen a chain 5 times using their big machine before there is no more teeth remaining.  I wanted a sharpening solution that would accomplish a few things:

• It must work without electricity.  I don't want to bring a battery, inverter, or need to stand near my truck in order to sharpen my chain. 
• It must be simple to operate.  I am not a professional lumberjack and never intend to be.