Put the nuts and salt in a big bowl and cover with warm water. Make sure that you add a bit more water as the nuts will swell out and you might end up with the top level no longer covered in the water.
Cover with a cloth and leave to soak (not refrigerated) for 7 hours for almonds & macadamia nuts, for 12 hours for walnuts & pecan nuts and for 6 hours for cashew nuts (no longer as they might get slimy).
After soaked, drain the nuts in a colander and rinse with clean water.
In your dehydrator: Dry at temperature no higher than 65C for 12-24 hrs.
In your oven: Dry at temperature no higher than 65C for 12-24 hrs. Be sure to use the fan setting and put a fork or tablespoon in the oven door for the moisture to escape and prevent nuts from baking.