You did a good job on that coin. It is a shame to lose the green patina, but you have saved it for future generations. I rarely use renwax. The British Museum uses it on bronze artifacts, not on coins. A small tub will probably outlast you. TIF is right, all coins should be regularly checked for nasty outbreaks, those that have already suffered should be checked more frequently. People are probably sick of hearing my mantra, "BD is never cured, it is only in remission".
Thanks Pishpash, first thing I am going to do is get a bigger tub of renwax, then hopefully live longer (outlast).