I have used Zebo Grate Polish for years, to blacken and polish the cast iron bases of Traditional Victorian Oil lamps. I still have an almost full tube in my workshop cupboard. Before Zebo, I used it's predecessor, Zebrite Grate Polish. I can still remember when the name changed some time around 2000 and, apparently, a long time before that it was called Zebra, having been originally inintroduced in the 1890's. Zebo has not been available for a number of years, but the HotSpot polish packaging seems to be a fair attempt to relate to Zebo, whether it is as good, I have no idea. Fortunately, I still have enough Zebo to out last me, (he said smugly).
Edited to Add :- I have just looked at an advertisement for Hotspot Grate Polish, and it is apparently Water Base.
This makes it different from Zebo, which is described on the box, as "Inflamable"