Drying whole oranges is difficult due to their very high moisture content, which is why most craft projects use slices rather than whole oranges. There are a few methods to dry whole oranges, but none that leave you with a perfectly round bright orange coloured result. Drying the whole fruit in sunlight, the oven or a dehydrator causes the fruit to end up somewhat shrunken and occasionally discoloured. Cutting slits on the sides is the most common method but does leave the cuts visible. A final approach is to stick the fruit with whole cloves; this allows the fruit to dry over time and smells pleasant, but obviously leaves holes in the surface.
Place whole oranges in a food dehydrator on drying racks or in a low-heat oven in a single layer on baking trays. Turn occasionally to maintain shape. Leave in the food dehydrator or oven for 24 to 48 hours; larger oranges may require a longer drying time.
Cut shallow slits in orange peel from top to bottom without removing peel. Make eight to 10 slits on each orange. Allow slit oranges to dry in dehydrator or low-heat oven for 12 to 24 hours.
Poke small evenly spaced holes over entire surface of orange using toothpicks. Insert a whole clove firmly into each hole. Allow to air dry or tie with ribbon and hang up to dry.
Poke several small holes in bottom of an orange using a knife or toothpick. Gently squeeze out as much juice as possible while trying to preserve the orange's round shape. Place oranges in a dehydrator or low-heat oven for 8 to 12 hours; larger oranges may require more drying time.
Oranges dried on high heat or in direct sunlight will dry out eventually, but will usually shrink, shrivel and discolour, so these methods are not recommended for oranges to be used in craft projects.