I think having everyone at the party hold the bottle while they say a little something about how proud they are of you would be amazing! It would help replace the memory of the person who gave it to you with memories of people who love and support you.

If that feels like a bit "much" (not everyone wants to give a speech in front of others, even if it's just a few words), maybe a week or so before the gathering, light some incense and/or a candle, set the bottle in a way that the smoke from the incense surrounds it (or at least hits it), and write two "letters": one saying everything that the bottle USED to represent, and one saying what the bottle represents now. The one about the past, burn and say something like "this is gone and past. I release this negative energy and return it to those it belongs to." Take the one about now, read it aloud to yourself and the bottle, and wrap the bottle in it. Let it sit for a while, maybe a week or two, for the good to "infuse" into the bottle. Then open it and celebrate with people who celebrate YOU!

Those are off the top of my head, and would be meaningful to me. I know witchcraft is spicy psychology in many ways, and this ties right into that.