I usually pull on the dead ones and if they don't give way I then cut them off. I have never cut green leaves down as I was told years back that it wasn't advisable.

I've just cut mine right down to about a foot. There were lots of dead leaves this year, unlike other years, and they wouldn't pull out.
We'll see what happens !

Be interesting to compare notes later on then!

Each year I tidy them up about now, cutting out the long dead leaves along with a few of the green ones that have flopped over a bit so it looks nice and balanced, I look after a few of these in costomers gardens, all in poolside settings, what a great plant.

I use the same method as Sbg

Thank you everybody. All I need now is the get up and go to get on with it! Yes its a great plant for a poolside. I love it when it has the seedheads as well.