Always assumed it was trash. Like a signal bouncing all around in the 80's . Dug one up and found it was a coin spill of 6 quarters a couple of dimes and pennies. Go figure.
I know what you mean. I'll dig iffy targets when I first get started and as the day goes on my knees start giving out. Can slaw is a killer. Rings up a solid 43 sometimes. Just like a small gold ring.