Two vials (2 fl oz size each) were filled with tap water (NYC tap water), two new nails put in each, and EM•1 (Effective Microorganisms) was added only to one vial (left vial in image below): 1/2 cap (approximately 2.5 ml or 1/2 teaspoon).
On the vials are the dates they were started (9/22/2004), and in the background is the website of the NY Times showing the date the photo was taken (4/25/2011), 6 years 7 months later.
The reason the rusted one ("water only" label) is cloudy in the photo is because in moving the vials, the rust particles were disturbed and kicked up.
In the one that's not rusted, the top of the vial shows rust because the air gap caused the very top to oxidize and rust, but the liquid portion has not rusted.
What may have happened is a combination of 1. where the microbes that do cause the rust have been displaced by the microbes (that are in EM•1) that don't, and 2. the EM microbes also produce substances (metabolites) that include antioxidants which help prevent oxidation/rusting from occurring.
Another nail rust experiment. Jar on the left is with EM•1 where at least the head of the nails still have their shine. Notice the amount of rust accumulated at the bottom of the jar of the non-treated, right jar.
