You can easily buy gold in most countries. I don’t think you’d even need to try as hard as the other person suggested.

If you really wanted to be cautious, you really just need to remove anything identifiable and slowly sell them at different “we buy gold” places. You could even get fancy and buy a coin press. If anyone asks (they probably won’t, these places aren’t exactly scrupulous), your grandpa collected gold before he passed and left his collection to you.

Or if you want to be a bit less cautious, just claim you found them in your yard.