muriatic acid is one of the few acids availble to regular people. its a
hazard like everything else if misused. most drain cleaners are dilute
forms of this.
you must be careful and not splash it on clothes or anything else.
I opened window, unscrewed lid, took deep breathe poured carefully and
left immediately shutting door. 15 minutes later I reentered, flushed
once and left, although the odor was largely gone by that time.
looks like the original poster is going to be doing lots of physical
work to clean hios toilet.
incidently I too tried lime away and other less volatile liquids that
were acid based. they did NOTHING! So I did muriatic acid, figured it
was that or new toilet.
the other stuff didnt react at all to the lime, whereas the acid
literally dissolved it, thanks to its being stronger