I recently got some coins that were collected by a relative who passed away and one of the dimes I found have "JP" engraved and in my opinion is a little to perfect for some one to just write it on there. Any ideas??
Well, people get bored? Bout the best answer I can give. Your coin is silver though. I'll give you that.
OP: An amusing side note to JP is the designer's initials, JS for John Sinnock, which appears below the neck line. In 1946 people thought it was a commie plot and that JS stood for Joseph Stalin.
There's a more amusing nugget than that: Mel's hole and the 1943 Roosevelt dime. You'll have to scroll down a bit: https://en.wikialpha.org/wiki/Mel's_Hole
Your dime is known as Post Mint Damage or PMD. Very common. I just picked up a Morgan Dollar with and "R" on it. It lowers the value. Your dime is silver so it's worth a wee bit more than a buck at today's low prices. Any chance someone in your family has those initials?