Good question. One of the two nozzles on each side of mine have gone a bit rubbish. If I can find a needle, I'll nip out now...
I never knew that, the jets are clipped underneath the trailing edge of the bonnet. The needle made no difference but I took the jets off (pull - HARD) and blew a mouthful of spirit vinegar through them from each end to dissolve any build up, re-attached and PERFECT.