Buy an ultrasonic cleaner, loads of lads on the audi-sport forum have, I've done it aswell, £35 for the small tank, it works as well as I've used it on watches etc...
I found the idle improved, the only thing I noticed with injectors out where 2 lower o-rings were showing signs off wear, so I replaced all 4 bottom ones, but the ebay price is very reasonable. I think dealers stock them at £5 a ring (8 rings over four injectors).
If not don't Dave on here have access to some ultrasonic gear?
