Hey Calan,
I have never tried it but- I have a friend(very experienced electronic prospector) that notch programmed one to all the square nails and assorted trash you find on the goldfields. He took it to a very trashy spot in an area that had produced lots of gold. He was unsuccessful that day. If I remember correctly he said the recovery speed was so slow that he could only creep over the ground. He hasn't tried it again so maybe he discarded the idea -probably because he has dedicated gold machines, a couple PI"s, Eureka gold, Gold bug II, etc...Hope this helps.
L8tr,
Merton