Although some sources do not recommend drying oranges because of their high juice content, it can still be done. Dried oranges can be ground into powder and used as flavoring in beverages and teas, as well as an aromatic addition to craft projects and potpourri.
Make sure that the orange slices are brittle, as dried oranges tend to mold if any moisture remains.
Store the dried orange slices in a clean, dry, airtight container, in a cool dark place.
Note: You may opt to dry the peel only. When drying orange peel, remove as much of the white pith as possible, as it is bitter. Dehydrating the rinds should take about 10 hours at the same 100 degree F setting.
Another alternative to oven drying, is the use of an electric dehydrator. The dehydrator has an advantage over oven drying, in that it takes significantly less time. Additionally, with the electric dehydrator you can eliminate the need for rotating and turning the fruit.