I've seen zips sewn to coconut halves so they could be zipped/unzipped
A Hawaiian bra?
Obviously relies on a certain breast shape and size, but coconut shells seemed to work well in the films of the 1950s.
Failing that, you could use them as rudimentary catapults if you add a bit of elastic.
Far better as a bra in my opinion... and the slogan could be 'Coconuts.... the ultimate breast protector!'
I would need two of those big nuts from the Seychelles
....Back to topic before I get banned: you can make all sorts of nice containers from coco shells, water, food, strong drink...
Knife scabbards.