Sounds like the best thing I can do is the poor man's flush?
Not sure what you mean by that, but get the correct fluid and drain/fill the pan, then swap out via the cooler lines. See this thread about doing it on a G35 - newer a little than yours but I think about identical:http://g35driver.com/forums/v36-general-...e-make-diy.html
Since you really want it out, I'd do a pan fill, and swap the total system volume (~12 qts). So I'd get 4 gallons. Then I'd do the PS system too. Those get overlooked.