We investigate the properties of cones whose polars are solid in different
polar topologies. By a standard duality argument, we obtain a number of nec
essary and sufficient conditions for closed convex cones to be solid in var
ious locally convex spaces. From this, we can deduce easily the extensions
of previous related results. Furthermore, we construct a class of closed co
nvex cones in some Banach spaces, which are not solid but whose polars sati
sfy the angle property. This solves the Han conjecture in the negative.