On Fri, 12 Dec 2008 11:02:55 +0000, David Hansen
wrote:

On Fri, 12 Dec 2008 08:58:11 +0000 someone who may be
(D.M. Procida) wrote
this:-

I want to make an unopenable jam jar - one that will resist the
strongest grips.

What's the best way to achieve this?

Do you want the contents, or the jar and the lid and the contents?

Has it already been opened?

If you only want the contents and a proper jar opener will not shift
it then drill a hole in the lid. If the jar has not been opened this
will release the vacuum. If necessary the hole can be enlarged to
remove the lid.

David .Read the OP again slowly...LOL