I'd like to help but I'm not following you...do you mean what is sandwiched between the front & the back of the CD, the hole in the middle, or the CD case insert?

thanks, Karen

Karen, Thanks for responding. I mean the plastic surrounding the hole in the middle of the cd itself.
It's slightly raised.

Hmmm...I guess if it were me I would try either my Dremel tool or my hand-held jeweler's saw. If you have some kind of power tool like a scroll saw or a jigsaw, that would probably work, too. I don't have either of those so I can't advise from experience.
Most of the CD art I have seen is from rubber stamping, where they break the CD into segments and just work with the center area as part of the design. I don't recall seeing any used with clay but now you have me curious!

Karen

I just bought a Dremel (impulsively!), but haven't tried it
out yet.
I've seen some polymer clay projects about using cd's
for things like coasters and covering w/clay, then painting.
I'd like to at least try the coasters (mine keep accompanying my glass when I lift it :) ),
but I think that middle piece would keep a glass from sitting flat.

maybe just an extra layer of "junk" clay from your thinnest setting on the pasta machine would raise the level to the same height as the center. Then cover it all with your good clay and roll over with a roller/brayer to get everything leveled out.
To me that would be easier than removing the center or sanding it down to level.

Karen

I may end up having to do that (cover the whole thing with
clay), but I had hoped to leave the plain, shiny surface
sans clay. Oh, well. Thank you for your help.

I've worked a little on the cds but I used a heating tool & got the cd real hot & cut it with regular sizzors. I didn't cut just the middle though. I guess you could use a dremel for that.

I looked at some of my CDs and they're almost perfectly flat, except for a tiny ridge. I would think even a thin sheet of clay would smooth that right over.

Are you using old CDs? Maybe they're different...