Most of my coins are from the turn of the millenium or prior. So hopefully they are proper silver. I accept that their value is historical and sentimental because of the link to my grandfather. I don’t intend to ever sell, not that it would get me much. I will say that I do have one coin I think is worth maybe $1500 though. A very nicely preserved shekel of tyre, thought to be of the type paid to Judas for betraying Christ since they were the only type of silver coin the temple took in (or so they say). The rest, like I said, not worth much. But it’s certainly cool to hold something man made that is thousands of years old. I have a silver drachma from Alexander the great that’s in terrible condition, it looks like someone’s dental filling fell out. But it was minted by Alexander the frickin’ Great! Priceless!
Oh, definitely hold on to them. Generally, coins that can be associated with a more popular emperor/king are more valuable, so if you have some that feature or Augustus, Antony, Tiberius, Claudius or Nero (or Alexander!), they are normally worth more than coins featuring Alexander Severus or Carus or Jovian. Depending on the condition, of course.