Here’s a link to the fantastic British brainy-toys site Grand Illusions that I’ve been hoarding for awhile, hoping to someday reproduce the process and post it as a tutorial. I have tried sun-drying several of the largest orange peels I can find on suitable forms, and have made one functional round box that is quite small and ugly compared to these.
[T]his box is actually made from an orange, or at least the peel of an orange, that has been squeezed thin, shaped, dried out and ‘cured’. Originally an ancient Mediterranean art, the technique was revived in the 1980s by a husband and wife team based in California.
Using orange peel, grapefruit and lime peel, the skins are soaked for several hours in water, then turned inside out and placed over a mould. They then spend several days drying in the sun, and are then removed from the mould and polished. The boxes will apparently last for decades, although the natural scent of the fruit will only last 3 or 4 years.
They are no longer for sale, and the fairly old linked page, above, is the only web-based information I can find about the process. If you’ve got any useful info, and care to share it, please let me know, below.