Larry, I was talking about how much the VDI changes as you sweep over the target from different angles. I'm not saying others feel the same way but I use that tool when I'm picky. If it say keeps changing for example from 144 to 145 to 146 depending on which way I sweep over it then I'll pass it as odd shaped junk if I'm being picky. Or, if it reads say 144 and 145 from one direction but reads 146 or 147 or something from another, then it's changing by too many digits depending on which way I sweep. That's when I'll pass on it when being picky. Most round targets like coins or rings should read one or perhaps two VDI numbers at the most no matter which way you sweep over them. Not saying that's always the case. I've dug nickles that changed by 3 digits or maybe 4 or so depending on sweep direction. I'm just saying when picky I'll look for two numbers or less no matter which way I sweep over them. For sure if you sweep from one angle and it keeps changing by 3 digits or more it almost always is odd shaped trash for me.
But, yea...On the beach, the biggest rule is dig it all. I'd only do the above when there is a ton of trash present. I'd also only not dig a target # if it was a common trash item found all over such as a particular tab that a nearby beach bar or something is causing. Or, like he said, if the beach is loaded with zincs. If you have the time still best to dig them all as it could be a ring. Really in trashy beaches I'll just grid out a 20x20 foot area at a time and dig all signals no matter what # or how bad they sound or no matter how much the VDI changes. Using a long handled sand scoop is just too easy to be picky.