Jean-Louis,

> I confirm that macadamia shells are very hard. I succeded in cracking a few with
> a pair of pliers, but then it broke. So, I tried with 2 different ordinary
> nut-crackers... which broke too.

:-))

We love them!
We have found two reliable methods for cracking Macadamia:

1 Use the big nut cracker from Orkos. (I can't look up the
  name of the producer, now, but AFAIK it is imported from
  the USA. So it should be available there, too. It is a
  large thing that should stand on a table and it has a long
  lever that moves a small, sliding blade against the nut.

2 Use a 24cm (11") pipe wrench. It can be a simple one, but
  the lower arm of the wrench must be held on both sides by
  the upper arm. Otherwise it will break soon.

While Marianne uses the big cracker, I like the wrench. I
can take it with me everywhere and I can break all nuts with
it. And it is a good exercise for the hand. You will get a
firm grip, for shaking hands. ;-)

> Any tips to shell Brazil nuts?

Where can you get natural Brazil nuts?

-Karl