Tom , itīs an old German brand of metal-polish paste, much like Maas, Simi-Chrome.
https://www.ebay.com/itm/Autosol-Solvol-Metal-Polish-Shine-Cleaner-Protect-Remove-Rust-Chrome-Brass-Steel/154230925429Actually many years ago, i was quite taken by all the recommendations the other brands got on the Mamod board, and imported them at relatively great cost to test them out.
Polishing can be a pretty tedious task, especially when were talking entire bikeengines, of which i did a lot of years ago, so anything that could ease the process had to be tested.
However, Autosol remained my favourite, as both its solvent ability and abrasiveness seemed slightly higher to me.
Using it does take a bit of concentration though, when working on riveted Jensen boiler or similar, as it will gnaw through thin nickelplating pretty easily.