Removing Varnish from Copper

I just picked up an old copper piece that I would like to enamel but
it has varnish on it. Any recommmendations on what to use to remove
the varnish.


Pennybrite is great but make sure you wash it with dishwashing soap
after. I enamel and that is how I clean big pieces of copper. Al it
is a good idea to clean with a soap like ajax to get off all
chemicals. after put some of the dish washing soap on the piece when
it is dry and than spead it around. you only need a little. it hope.