If you were a victim of covert narcissistic abuse, chances are, you had been pretty much isolated, the abuse happened behind closed doors, and that is why a great number of people are not going to believe anything you say about this wonderful, charming, and supportive individual, i.e. the covert narcissist, who tends to play the victim of life.
Now, those who do believe you, they most likely have a story to tell about the narcissist, but also told you to move on, forget about him/her, and at best delete his/her photos, text messages, and throw away any other reminder you can find. I understand, they give you the advice with good intentions, BUT they have most likely not had an experience with covert narcissistic abuse and this is why I strongly advice against their suggestions. DO NOT throw away or delete anything that can serve as potential evidence, if the narcissist makes a return or begins to rewrite history, at worst, trying to make you look like the abuser. This is how you build your case.
To any trained eye, text messages in particularly reveal the love-bombing, the beginning of the devaluation, the struggles, the gaslighting, the manipulation from start to finish. Some services allow you to download and print out these written exchanges.
Photos document the places and events you attended together, reveal some peculiar information about one’s personality, or at worst document your physical deterioration over time.
If you kept a journal during the abuse or started journaling afterward, keep it going and at a safe place. Tell a trusted person where to find it, in case something happens to you.
Attend counseling or therapy and work on yourself. This differentiates you from the narcissist, who sees nothing wrong with him-/herself. Get to the core of who you are and how you got involved in an abusive situation. It not only helps you healing, move on, and avoid these situations in the future but counselors or therapists support your case and can give others a clear picture of who you are and the progress that you have been making. Write about this progress in your journal, too, if you have one.
Keep track of any strange occurrences or things that you heard by chance that prove his/her abusive nature not only toward you, but maybe toward others. Write down the dates and names of witnesses and what was being said and/or done.
All of this being said though, keep in mind that healing, moving on, and taking care of yourself should be your absolute priority. Do not waste your time making conversation. If a random person comes up to you and wants to gossip about your former abuser (be it an ex-partner, family members, co-worker, etc.), nod and change the subject (this is part of the no contact rule). You really do not need to keep this association going. It is most likely not only awkward or even embarrassing to be still associated with your former abuser but it will drastically hinder your progress. Tell the other person, “Thank you, but I have moved on and I do not wish to talk about it.”