The best way to preserve your out of shell walnuts is to vacuum seal them and then store them in the freezer.  We do not recommend vacuum sealing them and storing at room temperature because there is a slight possibility of some moisture still being left even in the dry nuts.  When you vacuum seal them you create an anaerobic environment and then store them at room temperature there is a chance of botulism toxin forming.  

You can also just put them in freezer weight bags and freeze them or in glass jars.  

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Nellie Oehler