I've had this cap for only 2 years and I just had it off and saw the terminals were blackend and sort of corroded. I could scrape off the residue but they are still black. Car ran fine. It's a MSD cap and I'm also using 8mm MSD wires and AC Delco Platinum plugs if makes any difference. I just wanted to know why this happened and if it might just be a bad cap or if all the MSD caps are bad.
Thanks

 

Ionization is what causes it, smear a small amount of dialetric grease on the terminals and the rotor button. I have also heard of drilling a small hole in the cap but go with the grease 1st.