Battery acid looks like water, clear. Corrosion is usually lead sulfate, a white powdery looking stuff, or copper sulfate, a greenish powder. Not sure what red is.
However, clean the battery and terminals with a brush, plenty of water and a little baking soda (Dont get the soda in the battery vent). (remove and clean the terminals. Battery terminal brushes are cheap at your favorite auto parts supplier)
Rinse well, dry, and reinstall terminals.
Coat terminals with a barrier (Opinion vary on this):
Petroleum Jelly
White Grease (Lubriplate)(I use this mostly)
High Tack (A red goo used to make gaskets sticky, made by permatex)(I've used this too)
A coating made for battery terminals (whatever).
You will have increased the life of your battery and alternator by having clean, tight, coated connections.
