I tied a tiny needle file to my magnesium blocks. I took a regular small flat needle file and cut its length in half to about the same length as the magnesium block. I then sharpened one edge with a grinder, and burned a hole in the plastic orange handle for a lanyard connecting it to the magnesium block. I used the file to get shavings off of the block and the sharp edge I had ground onto it was used to produce sparks. Worked for me at least.