[kali_00]

I would guess by reflecting light off something silvery, eg, a wall painted in metallic silver paint.

[DonHopkins]

That's not how colored light actually works. (That's the joke!)

There isn't a silver "color" of light, it's a visual phenomenon that warps and reflects the color of the environment around it.

So unfortunately there are no silver colored light bulbs (except for using a silver coating to block or reflect the light).

Maybe it's that shiny reflective things like disco balls are therapeutic, imparting modernity, sophistication, intuition, reflection, coldness, or disco fever.