Turning tagua nuts
I too have wondered what one can do with these things. Here is some info to get you started
"Here's Some Tips On Turning Tagua Nuts
Select the so called bottom of the nut, other end is pointed in most cases. I then grind the bottom flat (using a belt sander) to about the size of a dime, but you can position the nut any way you want by studing the character of the nut for optimum usage for what you are trying to turn. I then use a hot glue gun. Using Hi Temp glue sticks, not the low temp craft type sticks. I have several small cheap face plates made from a nut(the size of your arbor thread, mine is 3/4 x 16 and a large washer. I find large washers (2 - 2 1/2" dia.) with a hole large enough for the nut to fit the hole. Then tack braze or weld the nut to the washer. Drill 4 holes in the outer washer and screw it to a piece of two by four and mount it on the lathe and turn it round. Even if your face plates are a little off round or wobble some, the end with the wood surface will be true. I then squirt hot glue on the wood face plate and press the tagua nut into it. Let it cool or dry for a couple of minutes. Then screw the face plate on the lathe. I turn these nuts at about 2500-3000 rpms. Lets say I start out to make a small vase. I break through the center void and now the vase is ruined. Don't give up, just continue on for a small bowl, if this don't work, I still have a small piece left on the face plate, I make a dish out of it. I cut the wood down just a little and re-use the face plate over and over. I don't think I have ever had two items alike in the hundreds of turnings I have made, because of the center void is the main factor you have to work around and contend with. I finish the vegetable ivory with sand paper and polish on a cotton wheel with any white polish compound. Making minitures in vegetable ivory is a rewarding experence.
Article by Robert Spragg Sr."