I would take a picture but that nasty so let me just say it is a filthy toilet. I usually pour in some Ajax and a quick scrub but many issues remain. What chemicals and tools should I be using?
I hope this is a real post, because if it is, it is awesome!
I am semi-eco in my bathroom cleaning. I like the "natural" toilet bowl cleaner you find in natural food stores that smells like cedar, I cannot remember the brand. But any thick liquid/gel toilt bowl cleaner will work. Layer that shit on the walls of the bowl and up under where the spigots are in the bowl. Let it sit for a minimum of 15 minutes. Use a scrubby or rag to clean, the brush is ineffective unless you are a weekly cleaner.
If you still have stains, I understand the magic eraser is good. Oh and...
DO NOT flush anything other than toilet paper down your toilet. That can cause blockages.
Frankly, though, if Ajax and a scrub isn't doing it, I don't know what will. If it is a stain,then the magic eraser, but if you have hard water, you may need a limescale/calcium remover product (they sell a "green" version of that as well! And it works!) to get rid of the buildup.
Good luck.