I have tried on more than one occasion to make polymer clay cabochons. This is my latest attempt.
I finally, finally after what feels like a bazillion tries got a nice shiny surface! I really took my time with these and spent a lot of time getting the surface nice and smooth. Then, I used rubbing alcohol to smooth the surface even more before curing. After they cooled, I sanded them with progressively finer grits of sand paper (320 to 1000) and buffed them with my Dremel.
Here is one of the cabochons being used for a bead embroidered pendant.
I'm still pondering how exactly I want to finish this off.
Next plan is to make cabochons with the polymer clay version of "mokume gane". I've failed spectacularly at that technique repeatedly. (Mokume gane is a Japanese metal working technique that emulates wood grain).
Hopefully, I've figured out my problems and can make some nice polymer clay mokume gane cabochons (in Christmas colors. . . ). And, I want to see if I can get an even shinier surface by sanding down to 2000 grit.