  In this paper we compare the brushing number of a graph with the zero-forcing
number of its line graph. We prove that the zero-forcing number of the line
graph is an upper bound for the brushing number by constructing a brush
configuration based on a zero-forcing set for the line graph. Using a similar
construction, we also prove the conjecture that the zero-forcing number of a
graph is no more than the zero-forcing number of its line graph; moreover we
prove that the brushing number of a graph is no more than the brushing number
of its line graph. All three bounds are shown to be tight.
