Can you help me with my car?

Two questions actually. When I had my car in for an oil change, tire rotation and diagnostic, the guy came back at one point and told me that I had the beginnings of corrosion on my battery posts and they’d be happy to clean it for me for the low low price of twenty eight and some change. This seemed ridiculous so I told him hell no, get back in that garage and just do what I asked you to do. When I want your input I’ll beat it out of you. (politely) Actually, I just said no thank you and was the soul of courtesy the entire time. But I thought they were a bunch of scammers who took one look at me and said “Oh look, a girl. Bet we can just make shit up and she’ll fall for it. Let’s draw something out of the hopper. Whaddya got Mike? Battery posts, yeah. She’ll fall for that one”
Really? Thirty bucks to clean a battery post? Does it call for a hazmat suit and respirator? Do we need like, a team of specialists with lab coats and clip boards? (Actual question now) 1. Can’t I clean my own battery posts with a wire brush in about a minute? And;
2. What, if anything, can I buy to lessen the look of a couple places where the paint has been scratched – not all the way through? I love my car and want him to look nice, and the two imperfections are right near the driver side door handle.