If you follow THEIR process of disassociating yourself, you are only validating their practice of judging and shunning. Don't give them that power.
If you do not consider yourself a JW, I bet most JWs that know you don't consider you a JW anymore, either. Just cut your losses and stay gone.
The only thing disassociating yourself will do is put your family in a very, very bad predicament. They will be forced to choose between their loyalty to you or to the organization. I guarantee if won't be you. It never is.