Anything acidic will work, and the more acidic the faster it will work.
pH scale goes from 0-14
0= acidic
7=neutral
14= basic
Batery acid is about 1
Household lye is about 13
Distilled water is about 7
Lemon juice, vinegar, coke, are all slighly acidic. I think molasses is as well, but not certain. Bicarbonate or baking soda is slightly basic. All are used in the kitchen during food prep. You can eat acids (or bases) if they aren't too strong. Your body will make and add acids or bases to your stomach after eating to adjust for proper pH during digestion. But, these have limited strength and slow response time.
Theoreticaly, you could puke in your gas tank and it would remove rust, too!
Who'll be the first to report those results?
Cheers,