I find that the most effective thing to bring on nostalgia is scent.
I can be walking down the street and can catch a whiff of the aftershave that an ex boyfriend used to wear 20 years ago and BAM suddenly I'm there and all the memories come flooding back to me.
Holy smokes that's incredible.
And you are so right now that I think of it smell triggers such nostalgia.
God bless.
Namaste :)
:)