On Fri, 5 Jul 2019 13:39:50 -0700 (PDT), les24preludes
wrote:

The brass will be soft enough to be cut easily by the teeth so that it can reach
the bottom of the groove while at the same time hard enough that it
will hold its shape a while. When it stops working just file the end
of the brass rod flat and start over.
Eric

Does this cleaning process work with copper as well as brass?
Copper will work but it won't work as well for as long. 1/2 hard
brass, the most common hardness when in rod form, is just the right
hardness. Practically any bronze will work as well. Avoid aluminum
bronzes. But silicon bronze will be fine.

Eric