How can I clean this toilet? (Horrible photo!)

[Sexisthairdressers]

Just that really. It's old and gross. I would prefer to avoid nasty chemicals. Any ideas welcome! Thanks all :-)

I "inherited" a toilet like that once. It was an attic conversion where the macerator ran every time you flushed it, so anyone who just had a pee in the night would leave it without flushing.

I chipped away at the worst of the limescale with a long screwdriver and fished out the debris in handfuls with Marigolds on. Then I did a couple of 24-hour overnights with vinegar (I didn't know about spirit of salt, aka hydrochloric acid, at the time). A few more scrapes with a wire brush and it was pretty much done.

Now I give the loo an 8-hour soak with 250ml of vinegar once a month. It's a lot easier to clean (with ordinary toilet cleaner liquid) after that. Of course, flush the vinegar away first.