I left in outside in the garden and it has rained. So buttermilk has had Water added. Not for the better.

This morning I gave it a tour with a toothbrush. Inside it has some effect - but inside is also a lot of surface. Even surface.

Also on the outside i has been cleaned. But Again mostly on the top. Where the brush and my fingers has most effect.

Dont know - I think that its the mechanical that Works. We see this afternoon.
But a lot of dirt was also removed this morning. It made the buttermilk darker.
The one WHO told me of this method explained that I would get a colour that had a ..... (dont know Word) but not as shiny as polish. Could he have been taling of the Black & White efffect?