I admit that I let it get very bad. Lived here for a year and a half and it's been building that whole time. (Does pregnancy and baby slightly excuse this? Not sure).
In the last 2 days I've tried- denture tablets, cola, white vinegar (undiluted with toilet water removed first) twice, all having been left for 2 hours and have a good scrub with brush throughout and after.
Although progress has been made, it is minimal. Some bits have chipped off at the top but the depth of the bowl is showing no signs of remorse.
Any ideas??
I got sold something called 'one stop' at a local hardware store but after looking at YouTube vids I'm way to scared to try it.