Sometime around 2009 the government banned Vanish and Sani-flush because it contained Sodium Bisulfate.
The crap it has been replaced with is terrible at cleaning toilets and removing hard water stains.
It also had the effect of helping to keep older toilets flushing because it dissolved calcium buildup in the jet hole.
use this information at your own risk.
You can't get real Vanish or Sani-flush but you can get the main ingredient that they used.
Just go to a pool supply store and buy Ph- but make sure it says on it sodium bisulfate or sodium hydrogen sulphate.
keep in mind this is pool acid and don't handle the crystals.
place 1/2 cup sodium bisulfate in the toilet bowl let it sit a few minutes and stir it with the bowl brush. wait 15 minutes or longer then scrub as normal. Sodium bisulfate does not fizz or bubble like the original vanish or sani flush because the bubble were for show they did nothing other than neutralize some of the acid made when the crystals dissolved in water.
The remainder of the ingredients was a surfactant (sodium lauryl sulfate), blue dye, and wintergreen scent. Only the sodium bisulfate did anything.
I use it all the time now.