When I was in England in 2011 I went to the Hollycombe Steam-in-Country museum, where they had all sorts of working steam engine equipment. Along with this were various historical bits and pieces, and I photographed a sign, which led to me wondering what the stuff was.
When I used the image at Just Add Light and Stir, I figured I better look it up in case someone asked. It was a polish for stove grates that put a layer of graphite on them that made them look silvery. So that association with coal would have been part of the reason it made the cut at the steam museum!
With my good friend Google search, I found this discussion on a Steampunk discussion forum: Zebrite, Zebo, Black Grate Polish, Black Lead - just Graphite ?
That linked to a letter to the editor of The Northern Echo, 21 March 2003: Farewell Zebrite, by an older hardware-business worker who was mourning its disappearance. Or ranting about it, as mourners sometimes do, maybe.
Nowadays, a new company is selling safety lights for crosswalks (called "zebra crossings" in the UK, with a short "e," not long) called Zebrite Belisha Beacons. Sometimes old products go away and the references to them remain in how-to books, or in instructions for doing things. I remember being a kid and reading about projects that involved things like oil cloth, and soap flakes, and being told by my mom or my aunt or my teachers that those things used to be common but aren't around anymore. Sometimes a recipe book will suggest a commercial product I've never heard of. I guess someday directions that say "add a box of Jello" or "...a can of cream of celery soup" won't make any sense. (And already might not outside the U.S.)
So knowing that we live in the flow of change is something anyone interested in learning or in history, or in learning history, might want to learn to appreciate rather than to resist.
What has changed? Some once-important products are long gone. Modern construction becomes historical architecture even while people are living in it. Clothing styles "come back." Musicians "cover" older songs. Movie costume and make-up can reflect the time movies are made even if the costumes are supposed to depict centuries past. Readers can look at the science fiction of 50 or 100 years ago with nostalgia for what people used to believe might make future sense.
People make their own connections, involving cars, hair, maps, science, language, furniture, food and humor, so a rich life provides the materials for learning history.