The long fancy bits on the ridge are called crestings, ridge capping or ridge decoration. The pointy bits at the end are called finials.

Try this technique:
* Stand well back from the job.
* Rest your pole on the edge of the roof so the brush is just touching the ridge capping. Then you can gently rotate the brush CW and ACW and wriggle it left and right and up and down to get into the recesses.
* Don't push too hard, rely on the bristles to do the work, NOT brute force.
The dodgy bit is cleaning the finial as this can just pop off when you're cleaning the back of it. And getting it back on is a BITCH.
If you can't get tfr, I've used Flash. It stinks of lemons, but does the job.