Did you go to the Christingle service and now have some sad oranges that look destined for the bin? Obviously they can't be eaten, but if you slice them carefully you can salvage a few slices from each which can be dried and turned into Christmas decorations. The most ecological (and cheap) way to do this is using the microwave oven. 

Simply lay the slices of orange on a couple of sheets of kitchen paper on a microwavable plate, set the appliance to its lowest setting and heat them for 4 mins. Test them to see if they feel dry and 'leathery' and if not, keep popping them in for another minute until they go. Stored in a dry place with your other Christmas decorations (e.g. a sealed tin, to deter mice!) they will last many years.