Hi,
Fieldstripping a luger for cleaning and lubrication purposes is actually very simple. I usually use a plastic wire brush for basic cleaning, then a cloth brush with a tiny amount of oil to finish it off. This is for simple cleaning after shooting. The brass wire brush works fine if the pistol really has a lot of crud in it, but once you get it to a servicable level again, you won't need it that much.
Here you can find a quick reference to luger fieldstripping:
http://www.vlimmere.demon.nl/Parabel...dstripping.pdf