Holy shit guys... I really gotta wonder how dumb some of you guys can be.
http://www.bcvids.com/dload.php?action=file&file_id=1
Go to the store, find the stumpremover mentioned in the video and follow directions in the video. If you can't find that exact remover, write down the kinds they have, come home and look up their MSDS sheets on google. (MSDS sheets tell what all is in a product and the safety measures that should be taken around it)
Anyways look in the MSDS sheets for one that is 95%+ KNO3 aka Potassium Nitrate. Then follow the directions in the video.
If you STILL can't find it, go to a farm supply place or some sort of plant store, they should have fertilizers that contain lots of KNO3. Again, look up their MSDS sheets and find one with a high ammount of KNO3.
However be warned, don't go to a farm supply house and straight out ask for KNO3. Either they will not know what your talking about, or they will call the cops thinking your about to build a bomb.
Yes, I am the guy that owns & operates SpudFiles (along with our extremely helpful moderators).