Just finished doing some work with RLPO, a pretty full on programme of Spanish music with loads of harp throughout, and one of the pieces was El Albaicin from the Iberia Suite by Albeniz.
I hadn't played that piece before so I wasn't quite sure about the direction on the music Mettez un papier entre les cordes especially as I was playing right up to the last note in the previous piece and there was only a very short pause before the start of this piece. Which didn't leave much time to turn the page, change the pedals and then thread some paper through the harp strings! But checking with the conductor in the rehearsal he definately wanted the paper between the strings.
What a racket!
It makes a really loud, raucous and horrible sound. I was very unconvinced at the start, but actually by the end of the week I quite liked the effect.
However you need to play very quietly because it makes an incredibly loud sound which cuts straight through the orchestra sound. Plus you have to play extremely rhythmically with very full articulation with as much damping as possible.
Sounds a bit like a buzzing mosquito when you get it right and sounds completely rubbish when you don't!