Dried poobits on the sides of your bowl. They happen to every toilet. They're the acne of the porcelain throne. Once they're dry, They're super hard to scrub off, so you scrub extra hard and end up scratching the porcelain, which makes it nearly impossible to keep unstained. But there is a better way.
This one is extra especially for the fellas and sharpshooting ladies, but it's good for brushwork if you (yawn) prefer.
Step 1: Weaken the Enemy
Place a square of toilet paper so that it covers the offending poobit, with its bottom edge trailing in the water. The water will wick up the toilet paper, soaking the entire square. Go do something else for a while.
Step 2: Vanquish the Poobit
The next time you need to pee, focus all of the pitiless force of your manly or womanly stream upon the helpless poobit. Victory is yours.