I'm so sorry that you lost your Aunt, we have so few relatives that the non-JWs (the ones who will speak to us) are very precious. What was she like?
If it's any comfort (doubtfully), my JW family have made my non-JW family lose interest in me by being better at the game... they know their propaganda and there are far more of them than me. They must be telling the truth, right?
Its better this way. I'm going to use the "if you can't say something nice, don't say nothing at all." rule.
Good call: I have decided to take total control of the contact I have with my poisonous folks, however much I love them and am worried for their mental and emotional state. I visit their hometown once a year just to see my non-JW grands, and I make contact with my parents at the same time. Last year it was a horrid experience; this year I'm going to bail when it gets ugly. The most important thing to my parents is how they and the organisation look to outsiders; I get the impression that if I cut them off they'd be happy because they wouldn't have that bad feeling from staying in touch with me and they'd get to say that it's my fault and my choice and that I have shunned them.
Be prepared for the long haul. If it's normally months between contact with her, expect to go for a couple of years before the silent treatment takes effect. You don't need to tell her that this is what you're doing, just don't make contact. For a while she'll be hurt, then she'll be indignant. She might eventually soften, but don't hold your breath. Spend the meantime enjoying the peace - it's the best thing for you and your family to protect yourself from this kind of treatment.