  We analyze some consequences of the Casimir-type zero-point radiation
pressure. These include macroscopic "vacuum" forces on a metallic layer
in-between a dielectric medium and an inert ($\epsilon (\omega) = 1$) one. Ways
to control the sign of these forces, based on dielectric properties of the
media, are thus suggested. Finally, the large positive Casimir pressure, due to
surface plasmons on thin metallic layers, is evaluated and discussed.
