I had a problem starting my S70 yesterday. Started fine in the morning for a short city driving trip, but then a couple hours later, it wouldn't even turn over. Was able to jump it, and then I let it run for a while to charge it up, but when I came back out a half hour later, it had stopped running (oil, battery, and CEL were on). My initial thought was the alternator, but there is also a good degree of turquoise colored corrosion on the battery positive terminal, so I'm wondering if this corrosion is preventing proper charging. Maybe if I clean the corrosion, the connection will be stronger and the battery will charge. Or is the corrosion a sign of a bad battery altogether? If I do clean the corrosion, what are the best methods to use?

Thanks a lot for any suggestions.