You can also still by the product called "Chore Girl" or "Copper girl" or something like that. It is like a steel wool pad, but made of copper. Available in most stores and grocery stores.
As for the rust in your pans.......not sure if is just in the bottom or a serious detierioation. It is normal to get a bit of "rust" if you clean and let your cast iron sit with water in them. Always wipe with a bit of oil after cooking and before storing.
Try this.........put 2 tablespoons of oil in the pan.......rub it all over the inside......heat the pan and then pour off the excess and wipe clean with a cloth. There should be remaining a fine oily residue on the pan. It should be fine to use after that.
Mostly though.........limit the cleaning with water. Cast iron need "seasoning" and water makes it exposed to air and rust.