Author here! I read about DStretch being used on rock art to discover hidden images in a thread here last month (https://news.ycombinator.com/item?id=49645437) and thought it would be interesting to apply it to museum artifacts. So I did, and it was! I ran it over ~4,600 high-res photographs from the British Museum, the Met, Berlin, and other collections, and then slowly went through them looking for anything out of the ordinary.

You can see my favourite results in the post. The color stretched versions are false color (they probably weren't bright neon) but the hues are likely generally in the right direction. The overwhelming majority of artifacts didn't show anything at all, but the ones that did were wild. It took a lot of time to sort through these, and I can only imagine there are a lot of objects in other museum collections that haven't undergone technical/fluorescent photography where you could find something if you looked.