[Heiko]

Jay, cleaning a dirty tensioner solves only the clean travel aspect of the tensioner, though it does not address the loss of the worn spring pre-load in an old tensioner. If you got 10yrs plus out of the old tensioners I think it's worth replacing them as the old springs will definitely show signs of fatigue.
Pumping up the tensioners will oil is easy, and it's an easy job swapping them out. If you don't pump them up with oil and let the engine cranking over prime them, you may stand a chance in accidentally skipping a tooth on the adjustment. Always make sure you prime them before inserting the new tensioners so that the tensioner doesn't totally compress quickly upon first startup.
As promised, I will change your tensioners for you when you get them :-)
Cheers,
H