Scratching with tattoo machine needles
In scratchboard style you reveal clay layer by scratching paint. White kaolin can be then dyed with thing color washes.
Tools made for this work are quite expensive and they loose sharpness soon. I ordered for testing these tattoo machine needless that have same structure as scratching tools. There are thin steel needles soldered side by side. First tests look promising. Lines are a bit thinner than in official tools. But for some details like feathers this tool would be great.
I will try to make wooden reusable handle for these.