2001 Hyundai Santa Fe Air conditioning and battery

You see what they don't tell you at these ac places is, if your a/c needs to be refilled, then you have a leak in your system. Now if you had it filled last year, its gonna come out again, how fast or how slow depends upon how big the leak is, Now that red stuff on your battery post, I have no idea, the only thing I can think of is maybe someone spilled a little transmission fluid or something. Thats strange, I never seen or heard of that happening.