Hello Andy
Loctite gasket remover is made to work with aluminium and did this very well although I was surprised to have to get it online as the local parts shop has stopped keeping it. As for lacquer, I just found an automotive lacquer that claimed to have good adhesion to aluminium. If that claim is as good as its quick drying claim it should be very good, time will test that, but I am sure it won't last for ever anyway.
Dave
