That's a great collection, and I agree with what AnotherBob said about them. There are several in there I'd really enjoy having in my meerschaum collection. Whether you display them or end up smoking them, you have a fine display on your hands.
It sounds like from your original post you would like to display them. IMO, gentle wiping with a cloth to remove dust is all I would recommend. The “patina” of a well-loved and well smoked pipe gives character and authenticity. Display them as is as a history of your grandfather.
That elephant is extremely cool and the long one I always wanted one but im a caveman and I feel like the first time i pull it out id break it for sure.