Lemons. There are some commercial cleaners that are citric acid based I believe. Just dont use it on your equipment. I dont believe lemons would cause much damage, citric acid is a fairly mild organic acid. Its in a lot of stuff.
Two Raven Brewery
[Is finally brewing again!]
Primary1: Envy - Green Tea Wheat (4/11/09)
Secondary: Schwarzbier Kit (1/11/09)
Bottle Conditioning: None ATM
Drinking: None ATM
Up Next: Lemon Honey Pilsner (est. unknown)