Intro And Question On Dipped Coins

Hi, I'm a 67 and a retiree with a rediscovery of my childhood coin collection. First, hello to everyone--I hope to be a regular contributor. Second, I have been buying coins from Esty and ebay and have a question on dipped coins...as in, how do you tell when a coin has been dipped.

Now I know you are probably going to say that if it's shiny it's been dipped but I have coins (silver) from the 50's and 60's that look every bit as shinny as when I bought them.

Now the problem is, if this is a problem, is that I have been trying to buy the best coins I can reasonably afford. Now in terms of quality, I've been looking at the back of the coin to see how it compares to the examples on the internet. Now the problem I'm facing is that the closer I buy to uncirculated the shinner the coins seem to be.

From the sparse reading that I've done, the older the coins are the crustier they are. So am I to assume that everything that I've bought has been dipped...I've got BU from 1916 up to 1945 and you need sunglasses to look at the lot.

Thanks in advance,

Peter