It rusted faster in lemon juice.
I once cleaned pennies with white vinegar and salt ..it got the rust off of them ..I don't think pennies exactly rust ?
The liquid that rust a penny the fastest is vinegar.I had a science fair project and my topic was in what liquid does a penny,sewing needle,nail and paperclip rust the the fastest and the penny rusted the fastest in the vinegar rather then oil,water and saltwater.
Pennies don't exactly rust but they do react to water fastest. You can research like I am too. I have to do this for science class as an easy "lab" project. The water is fastest because it has more molecules than coke or whatever. Do the experiment.