caking up

[ccarmo]

Hi, could you please explain the meaning of the following sentence:


She slowly dug her thumbnail along a plank of the seat, provoking a splinter but caking up mold and disintegration instead.



Thank you

 

[Anglika]

What I think it is saying is that she wants to get [provoke] a splinter of wood from the seat, but that all she gets is a cake of mould under her nail.