Same here, I only use the scraper side. I do take it out every time I use it, so it does not sit in my tank. No rust and they do make replacement blades, 10$ at BRS. Even though I take mine out and leave it out, it still sounds like it scratching the glass every time I use it, but it's not. With that said, I have quite a few big scratches right front and center of my tank from trying to clean corraline off with a scotchbrite pad. Never again will I use a scotchbrite pad on glass!
Think I read on here somewhere horror stories of scratching the hell out of a tank because a baby snail got stuck under the cleaning pad.
On a side note, hows your weather holding up? Heard your supposed to get a decent storm this weekend.