leaking fuel from an injector; '85 300D

So the other day when fiddling with the power steering pump, I noticed some "wetness" on one of the PS lines, like oil had been spraying on it.
Looking around, I noticed that the #3 injector has a ring of oil around it, in the joint between the nut and the injector body (i.e. not on the block), and the head bolt that's right there is filled with fuel as well. I don't see much indication of fuel spray, but I'd like to fix it anyway and the CD manual doesn't give me a whole lot of information. Can I just turn that nut with a suitably-large open-end wrench, or is it really truly preferable to disconnect the fuel supply and pull the glow plug to turn on this thing with a deep socket? I ask that because, is there a way to drain the fuel out of the supply lines in some way other than "disconnect and let it drip out all over everything"?
Finally, I've been thinking that maybe it'd be a good idea to look at the injectors to see, well, how they look on my '79 TD. Is "current working state" easily observable by eye? I've read here that a set of remanufactured injectors is only about $50 after core, so maybe I should just go ahead and swap them out? I'm curious though if I can glean anything with a visual inspection (been running mostly waste vegetable oil for about a year now in both cars).
thanks, -tom!
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Appears the #3 high pressure line is leaking at its compression fitting. Put a wrench onto the "nut" at the end of the high pressure line where it is attached to the nozzle and snug it tight. "Snug" means just that - only tight enough so it doesn't leak. Too tight will crush the compression fitting and the line will need to be replaced. So go slow and tighten it a couple of times if necessary - we're talking only about 10 or 15 ft lbs - a firm handshake.
The only visual inspection is on a test stand. The injectors are OK if the motor runs smoothly at idle with no knocking when cold and doesn't smoke too much when driving.
Nozzles are good for 100K miles, or more. Remanufacured nozzles are about $50 EACH plus core! So if you still want to change them get a 1 1/16 inch deep socket, new bleed off hoses and have at it.
The nozzles come out just like spark plugs - tight and suddenly loose. Keep the plastic cap on each new nozzle until you are ready to connect the high pressure line to it. Also know that the old nozzles are full of fuel and ought to be kept upright until you can drain them into a can. Replace the thick washer below the nozzle (new ones are included) and torque the new ones to about 50 ft lbs. This is a job to be done only when there's a need, otherwise, leave it be.
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I had a leak around one that was caused by one of the return lines that travel from injector to injector. It also pooled around the injector, but actually wicked up the line and on to the next one! A few dollars got me replacements for that.
tweaks
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