Wear either rubber or latex gloves while cleaning all surfaces on a toilet.
Most experts recommend a two-part approach when cleaning toilets weekly — inside the bowl and around the rim, and outside the bowl along with the seat, lid and hinges. Bacteria are all over the toilet, not just inside the bowl.
It’s never a good idea to mix different cleaning solutions or chemicals together, especially if you use a bowl cleaner containing acid and a disinfectant for the exterior surfaces.
Start cleaning inside the bowl by forcing as much water as possible down the drain. Use a toilet swab to do this; a plunger will also force the water through. Excess water will dilute the effectiveness of any cleaner you use. Apply the cleaner and use the swab or a nylon toilet brush to scrub all interior surfaces, including the area under the rim where the water vents are located. If tough stains are present, it can help to let the cleaner sit for several minutes or longer, then scrub again.
Flush the toilet and let the running water rinse the swab or brush. Wipe down the sides and top of the rim with a moist cloth to remove any chemical that may have splashed out of the bowl during cleaning. Then rinse the cloth well and wring it out.
Now, use a disinfectant cleaner on all the other surfaces — the bowl exterior, both sides of the seat and lid, on the hinges, even on the floor adjacent to the bowl. Let the disinfectant liquid sit on the surface for several minutes. An old toothbrush may be handy for cleaning out accumulated grime around the hinges and at the joint between the bowl and floor; add more disinfectant if necessary. Rinse and wipe away the disinfectant with a moist, soft cloth and buff all surfaces dry with a soft, dry terry towel.
To remove really stubborn stains inside the bowl, pour a cup of chlorine bleach into the bowl, close the lid and let the bleach work on the stains for a couple of days without flushing the toilet. This technique will work especially well “if you’re going away for the weekend,” says Jeff Bredenberg, editor of Clean It Fast, Clean It Right: The Ultimate Guide to Making Everything You Own Sparkle & Shine. “This is a good way to get rid of old built-up stains.”
Hard-water deposits — that stubborn ring or crust at the waterline inside the bowl — generally won’t respond to cleaning with bleach-based products. Instead, use a bowl cleaner containing acid or a mineral-descaling product after forcing as much water out of the bowl as possible. Wear skin, hand and eye protection while working with any product containing acid. Let the cleaner soften the scale for several minutes or longer, then scrub with a toilet brush.
If that doesn’t work well, you may use a green nylon scrubbing pad to remove scale or stains as long as the bowl is made of porcelain or vitreous china. Green pads are fairly abrasive and can scratch any other bowl material. If the crust remains and the bowl is white vitreous china, flush the acid cleaner and scrub the deposit using a well-moistened pumice stone.
Additional references:
Don Aslett, The Cleaning Encyclopedia: Your A to Z Illustrated Guide to Cleaning Like the Pros.
Consumer Reports editors, How to Clean and Care for Practically Anything.