Hello,I dug into a bunch of what I believe are cone top beer cans, but they are too rusty to tell any names or anything. How would you tell a cone top from some other kind of can? One of the cans still has a crown top beer cap type lid on it. They all have concave bottoms. With them I also saw one can with just one big hole in the top for drinking. So do you guys think I brought home a bunch of rusty cleaning fluid cans or? Lisa