My six year old daughter and a little neighbor friend just proudly brought in their haul--about 25 decidedly green lemons and about 50 not-really-ripe-yet oranges. I have a huge haul of lemons coming this year, but the orange tree set pretty lightly this year, so that's perhaps half of the fruit that was on the tree. I hate to waste it, but I haven't a clue what to do with unready citrus. Any ideas? Can it be used for marmalade?