Ad,
I can give you a couple of hints on Banksia Pods.
To clear the seed holes I use a small hooked tool from my electronics soldering equipment but a piece of wire with a small hook should do equally as well.
If you want to hollow a pod be prepared to use an awful lot of thin(ish) superglue. A little hollowing you can get away with, but for walls much less than 1/3 inch the hard sheath making the seed hole will become detached and fly out. You will need to turn down to an almost finished size, apply lashings of glue, all around every hole. Then you can finish the outside before tackling the inside.
But keep an eye on it, I've still lost a couple of the sheaths and spent many minutes grovelling in the shavings looking for it, to glue it in again.
Tip.
I've never yet found a way to thin superglue but I have discovered that if you drop the bottle (with lid firmly on) into your hot tea or coffee the heat certainly makes it flow far easier.
