Dig everything above iron unless you're in an extremely junky environment with layers of beer caps and pulltabs. As you may know gold will read all the way from foil to a zinc penny on your Target ID based on the size and its gold content. Plus your target ID is only accurate down to around 7 or 8 inches. After that its a little iffy depending on the size of the target. In other words, it may look and sound like its a piece of junk but if its deeper than the Target ID range, it may not be junk. It just might be a coin or even some gold. Also, you'll find more junk, but you'll also find a lot more rings and who knows what else if you lay off the discrimination. I don't know what a jewelry mode includes on an Ace 150 or 250, but if it gives you a wider range of targets over the coin mode, I would stick with it as long as it also included coins. More specifically, if you get a good repeatable signal above the iron range, dig it.