I use a file just like Heavy said. I ground mine thin, man the file eats it quick too! After the file I switched to a DMT XC to set a not so micro bevel. After the file and stone (10-15min) it's back to perfection. The CS factory "edge" is so lacking. Wait until you try a good edge on one.
I used mine today to clear heavy brush and small trees for three hours. Ya, it dulled to the point it's wont really cut you unless you try, but it still flies through weeds and wood. For the price they are great! Use, abuse, replace!