On 10/07/2018 12:41, J. P. Gilliver (John) wrote:

Kohl is also charcoal - I think it is even used in English in that sense
in the context of (especially stage) make-up. So I would imagine
Kohlschreiber is more likely to mean pencil or crayon than cabbagewriter
(-:

Aw, now you've gone an ruined a perfectly good joke!