Ohh.. Your neighbour better call the police about this one. Not much fun having something like this in the garage!
As you probably know, they will then give the job to the military bomb spesialists. Almost as a routine job for them.. Many shells are still beeing found here in Norway.
Here are two recent findings this year (articles are in Norwegian, but the pictures aren't
)
http://www.nordlys.no/nyheter/article6512983.ece
http://www.vg.no/bildespesial/spesial.php?id=10130