Two coins is a great score. It's just luck what they might be! In a trashy site like that, when you get a big low signal I use a long screwdriver to poke in the ground and you will soon tell an old can. The fact the house was built in the 50s may mean its time to use it as a test garden, but look at moving on. Detecting is about only one thing, Geography! You have to put yourself in the right place. You have done well so far! Clean out that site first, and you will have learned a huge amount. If you find great stuff well and good, but you are getting a great understanding of your machine either way. gl hh