I have had really good luck with the mr. clean magic eraser or a spray product called mean green tub and tile cleaner.
The body when making teeth. Factories making iron bathtubs.
Stainless steel is more resistant to stains,particularly rust stains,than white and enamel on the GE JP202.
Stains in an enamel bath may be able to be soaked out. Bleach on a cloth applied to the stain can lessen the stain and may get rid of it. An abrasive cloth such as a "Magic Eraser" may do the trick as well.
Never Dull works well with some elbow grease.
Toothpaste!
the production of enamel for bathtubs, stoves, refrigerators, and metal signs, and as an agent for ensuring brilliance and clarity in the manufacture of glass.
Tea stains teeth with prolonged usage while sodas break down the enamel of the teeth.
Quartz and onyx (minerals), marble and granite (stones), are popular surfaces for sinks and bathtubs. Ceramic, porcelain enamel, stainless steel, copper, glass, soapstone, nickel, concrete, resin, terrazzo, polyester, and wood such as pine, mahogany, bamboo, or elm are also widely used.
Since an enamel bath tub may scratch, it's best to use gentle cleaning methods. To remove limescale and many types of other stains and deposits, soak the affected areas with vinegar, then wipe off with a sponge. Hydrogen peroxide will also help many kinds of stains.
porcelain bathtubs are always cold and feel like glass and have no give. fiber glass and plastic tubs are warmer to the touch, soft and give if pressed on, Enamel when tapped with the hand sound metallic
I would use an epoxy paint or possibly a very high quality enamel. I would also lightly sand the entire surface with 600 -800 grit Wet 'n Dry to get good a surface for the paint.
You will need cement and nails to refinish bathtubs