Put a paper clip (the black triangular
heavy duty ones) on an unused corner, tied a string
to it and attached it to the pen.
Then submerged the board in etchant in a tupperware
sandwich container ('won't be eating
from that anymore). It was too big a container for
the board (waste of etchant) that
I was doing.
I was doing all this outside, and
it was cold yesterday, so the first 10 minutes went
slowly without much etching going
on. Then we brought out a hair dryer to heat the
etchant and keep it agitated (twirling
the board around in cold etchant gets tedious).