Our donor loco spent its last months as a Sandite loco - Sandite is a fluid used during the Autumn to increase adhesion on the railhead in order to mitigate the effects of leaf contamination. It comprises an adhesion modifier (er, sand) suspended in a paste which is delivered to the rail head as the loco travels along. In the process of applying it to the railhead it also liberally applies it to every surface of the loco underframe. We had a go at removing the bulk of it with a steam cleaner last year but the only way to removed the remaining bits was with a scraper and wire brush. The before and after photo below shows the fantastic single-handed result of months of work.