Hi

> I have the Spring reverb ...should the box with the springs inside be
> faced down so the springs are not showing and therefore no dust, or face up

Dust does not make any influence to the springs themselves, because the
electrical sound stimulation cause vibrations of the springs which
remove the dust.

In the opposite: There is also some advantage with a open side up
position. You can lay something on the springs, which changes the sound
of the reverb: Eg. aluminium foil, nails across the springs for
resonating effects, or a kleenex or fabric for damping.

Florian