After watching way too much Baumgartner Restoration, do paintings with such status receive much conservatorship? The varnish on that painting is obnoxiously aged.
The other important property is that these materials are often designed to show up visibly under UV light. That way they can perfectly blend in the base paint under normal gallery lights (if desired, this is not always desired) but they will always show up for someone who investigates the painting in the future.
1: All my knowledge about the topic comes from the aforementioned Baumgartner Restoration YouTube channel: https://www.youtube.com/c/BaumgartnerRestoration
I suspect, if given the job, he would only do it in incredibly small steps with deep collaboration with his peers.
I've watched how cautiously he approaches paintings which (while admittedly beautiful) don't have 1% of the historical significance of a Van Gogh.
His channel hits this incredible niche between science (his knowledge of how the various cleaning methods, glues, paints and varnishes he uses interact with each other is amazing), the technical (one of the first videos of his I saw was the vacuum table build and the rigs he's built to save some of the wood panel paintings are amazing), and the meditative (as he would say, sometimes there is no better way to clean a painting than sitting there for 12, 24, 72 hours with cotton balls).
I'm a bit sad that they don't allow someone like him to work on paintings of this vintage. I know a Van Gogh is extraordinarily perhaps incalculably valuable but I would absolutely love to see paintings as they were when the artist first painted them (or at least closer), especially Van Gogh. The transformations on some the paintings Baumgartner has done are astonishing and can completely change the tone or meaning of a painting.