Probe, check out this site:
Law
But of the 3 countries you list, it only has Lithuania. Thus restricting the conversation to just that one location, and looking closely at that text: You can see that it only applies to cultural or historical artifacts. Notice it doesn't define what (how old or valuable an object must be, etc....) to qualify as being old or cultural. Thus if you were plying the beach for modern tourist losses (jewelry, etc...), it most certainly would not apply. And in countries as old as Lithuania, it's possible that coins 100 or 200 or more years old wouldn't be considered "old" or "historical". Heck, in Britain, they get disgusted when they find coins that are *only* from the 1700 or 1800's as nuisance "new" stuff, haha. And let's be serious: is there anyone following you around with a calculator, doing the math on the ages of stuff you find ?
Bottom line is: it's not forbidden, as long as you're not looking for, or finding, "cultural" or "historical" stuff. Then presto, you're only looking for new stuff, right? And I had to chuckle at the consequences it lists: a "warning" for violations. Then a fine, but doesn't say how much.
Also be aware, that it is entirely possible that such laws apply to, of course, public land. They are public laws for public lands afterall. Therefore you could conceivably hunt private farmers lands, with permission, till you're blue in the face (helping him to find that ring his wife just lost afterall), and be outside the scope of such laws, since it's private land. That's what they do in England too afterall, where .... there too .... all resources under the ground, belong to the queen just like this Lithuania language. Yet you'll notice no lack of md'rs in England. And notice they're hunting private farmers lands 99% of the time.
As for the other two countries, I don't know. But even if you did find dire sound verbage, it might have the same resulting logical conclusions. Or be things, for example, meant to address raiding pyramids, exporting gold bars, public land (obvious sensitive historic monuments), etc.... Yet not apply to private-land with permission, or modern objects, etc....
