Here's what I did for our hazelnut challenge--
1. obtained in-shell nuts-- from supplier that (mostly) handles only those tree nuts (but also some walnut/almond), but DEFINITELY no peanuts--
2. Washed them in copious amounts of hot water and a single drop of dishsoap to act as a mild surfactant
3. Rinsed them in even MORE copious amounts of water
4. Dried on a cookie sheet in the oven, set at about 150F, for a couple of hours.
5. Cracked inside a large freezer bag, outside
6. Ground in a cheap electric coffee grinder.
Obviously, buying safe shelled nuts from a supplier that can assure you about processing is a better option if you have it.