The E404 Remove+ Battery Cleaner and Acid Detector features a specialized foaming agent which turns pink upon contact with battery acid. It instantly neutralizes, dissolves, and removes battery corrosion from battery terminals, cables, hold-downs, battery boxes and more. It is formulated to assure maximum current flow and reduce potential voltage leakage. Comes packaged in a 14-ounce aerosol can.
Tried it out on my corroded NEG Battery terminal and it worked great. It comes out as a yellow foam and by simply putting a paper towel around the corroded terminal, you can spray the foam so that it only covers the battery terminal. Let it sit for 2-4 minutes and then wipe and spray with some water, soaked sponge or towel and the corrosion is all gone! It turns out after wipe or spraying with water, the dye showed pink/red at the source of the acid. The acid was coming out of small cracks of the NEG terminal post. Cool...I knew then I needed to replace my battery too.