On Wed, 26 Jul 2017 06:44:12 -0400, Bob wrote:

Hello,

Could anyone please suggest a toilet bowl cleaner that
actually works, other than the one(s) that are apparently
nothing but Hydrochlorlic (HCl) acid ?

And, anything specific for that bluish-green stain
that is fairly common I imagine ?
Possibly some kind
of Sulfate deposit from the water itself ?

Thanks,
B.

ISTR, the blue stain is caused by acidic water in copper pipes.

Have you tried a cleansing power like Comet and a brush? Scrub it off
with the abrasive powder.