When you buy citrus you should always rinse it in a 10-to-1 water to bleach ratio (10 parts water, 1 part bleach) and let them air dry.
To store citrus longer you can get a 5 gallon bucket and fill it with clean sand. Bury the clean citrus in the sand and lightly pack it down.
The sand fills the pores of the citrus and it takes longer to go bad.
- Lynn from LA, USA