If your stains are light, you can cover the area with a baking soda & add a little water to create a paste.
Let it sit for 30-60 mins & wash it with a sponge. Everything will wipe away revealing beautiful clean surface.
Instead of making a paste, add about an inch of water. Bring it a boil over medium heat & then simmer for a few mins. Then turn off the heat & let it cool completely.
Once cooled, wash it with a sponge. If you still have stubborn stain left, sprinkle more baking soda & a bit of water to make a paste & scrub it with a sponge or scrubber.