Is 30 year old unopened amaretto valuable?

Answer 1

If you can find someone that collects alcohol related memorabilia perhaps.

Or if the bottle is in a decorative bottle, or was created as a celebration or commemorative collectable.

Typically however most normal alcohol is not widely collected (unlike wine). It will at the very least retain its retail value (if sealed, it will not spoil), and perhaps a bit more if you manage to find someone that collects interesting bottles.

But unless there is something specifically special about the bottle, its not likely worth more than retail value.