flame guns do work I have a cheapo 30 quid one, like a walking stick with a flame coming out of the end. It will take more than one go...maybe six or seven but loads easier than digging. If you have a large area to do, you can rent a big so and so here
http://www.hss.com/index.php?g=62610
this link says that salt works, which i remember my Dad using but it does linger in the soil
http://www.bycentrum.dk/garden/?gclid=CNaI7-GE spsCFU0B4wodoWfVOg



