The Boneyard in Las Vegas is also worth seeing. It was featured in one of the Danny DeVito scenes in Mars Attacks.
It focuses on Cold War era (gently phrased, ie the Soviet occupation) neon signage, and they're rescued a huge number of small to gigantic signs that made up Poland's visual landscape.
But I most appreciate trying to keep a record, a visual interactive record, of something present in cities that I hadn't even realised was silently vanishing. My favorite coffee mug is from that museum with a picture of the Kino Kosmos logo -- more locally, the Kosmos cinema in Tallinn closed recently and I feel its loss too.
They even run courses in creating your own pieces.