Are you talking about Tagua nuts, maybe? Macadamia's are a bit small for turning.
I had a stopper I had problems getting off the stopper chuck. In the end I used one of those rubber jar opening pads and a leather work glove.
This won't help now but next time. Always use a little wax or paraffin on the stopper chuck threads.....james
You can peel the cloth of the top side of some mouse pads and it leaves you with a great piece of padding. I use this foam from Mouse pads to pad my bowls when I reverse chuck. It should work on helping you get a grip on the stopper as well.
Good Luck,
Jack