That technique is called "acetone bath". Though, I'm not sure about the "poof", but originally the ordinary conventional oven was suggested where you put your print and a cup of acetone. The idea is that the very low oven's heat evaporates the acetone in the enclosed space and the thick vapor melts all the tiny imperfections evenly. That's definitely helping make nice looking pieces of art like dinosaurs skulls, but really hard to control if you need to mate some surfaces precisely. Also it works only with ABS (and some other plastics). The PLA is fairly resistant to the acetone.
Here is the trusted source on the subject with a more safe method as well: http://makezine.com/...-acetone-vapor/
In a case you really need smooth surfaces - sanding and polishing is the only proven way as usual. However, you can often alter your design to eliminate the need. For example you can leverage the fact that the PLA is softening in boiling hot water. Mating it with a metal part will remove all the imperfections preventing smooth sliding of that part (i.e. the eyepiece barrel) in and out with very high precision. Or you can opt for a multi-faceted surface which will be equal to the round one mechanically but any imperfections will be removed by the mating metal or plastic part. E.t.c.
Edit: PLA is very easily spray painted. I bet a brass looking epoxy paint is available, it creates very glossy, enamel like surface finish after curing in several layers.
Edited by halx, 09 January 2017 - 09:44 PM.