(AP) -- Phil DeVore pulls a folded piece of aluminum from a murky pond. The aluminum looks like a piece of siding that's blown off a building, but DeVore knows it's much more valuable than that. He slips a rubber band off the aluminum and unfolds it. He likes what he sees -- 50 or 60 glistening black leeches. They're your common ribbon leeches, Nephelopsis obscura to aquatic biologists.
After its initial use, cooking oil can be refrigerated or frozen and reused for another six hours of cooking (see References 2). Don't reuse cooking oil if it smells rancid or you can't heat it without smoke developing, as this indicates significant deterioration (see References 1 and 4).
Refrigerate fatty carrier oils to prevent rancidity. Essential oils generally have a shelf life of one to three years. Some get better with age, such as sandalwood oil, vetiver oil, and patchouli oil. The citrus oils are most prone to degradation, and should be used within one year.