For a White Porcelain toilet, iron-out works best for me. Follow the directions for clearing rust from the tank and bowl. One area where I've had stains is the side of bowl where the tank water comes out of the rim. To get those out without having to scrub, I fold up 1 or 2 TP sheets, dampen them, put iron-out on to the sheets paste and them over those streaks. Let it sit for 30-45 minutes, then flush. It's cleared them up for me. I've used pumice too and it's worked but I've had to scrub to get those off.