What is causing the positive terminal of my car’s battery to blacken?

Question by vmgalvez: What is causing the positive terminal of my car's battery to blacken?
I have a 1995 mercury tracer 1.9L I4 car with a battery that has the sufficient CCA for the cold here in Ohio. The positive terminal of the battery "blackens" for some strange reason. Everything is fine. I have good start whether in a garage or outside and I do fine reaching 60mph on the highway.

Best answer:

Answer by garidor
Clean both the post and terminal and coat both with petroleum jelly and reassemble, should fix your problem.

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