I thought I'd give my flugel a pre-area bath today and was amazed at the amount of gunk in the bottom of each of the valve casings. Its not that long since I last cleaned it, and I've never noticed the problem before, so I was wondering what it could be. The only thing I could think of is the valve oil I'm using is reacting with something or gunking up somehow. I noticed the crud is a similar colour to the valve oil I use - blue juice (sorry if thats too much information ) but I guess it could just be just colouring existing crud not actually causing it. I've used blue juice for a while now and I think its good stuff - in fact I've posted on here a couple of times to say how good I think it is, but I'm aware that there have been a few critical comments too. Is this why some people are critical of it? Has anyone else found this problem? For info I play a Bach Strad that's about 10 years old.