Dovo/Herold Red and Black Pastes

[thp001]

What are peoples opinions of these pastes. For me they don't seem like they do anything, as far as I am aware the red paste is some form of FeOx and the black paste is made with lamp black, both to me seem like they would be too soft to affect the steel. No evidence of swarf on the strop also seems to hint at this (obviously difficult to see on the black paste but would expect some on the red being advertised as coarser).

These are the small crayon pastes btw not the tubes.