Okay...it is my night off and I have had a few beers...so please bare with me on this if it is a stupid idea.
I read a thread on the AR15 board one time that suggested putting a good coat of militec on the bolt and carrier and sticking it in the oven on moderate heat to allow the militec to bond to the metal.
The XD finish has a slight reputation for rusting.  I found this first hand when I got my XD, new in box.  I gave it a good cleaning the day I got it and noticed a orange tinged residue (rust maybe?) on the heads of the Q-tips when I ran them down the slide rails with some breakfree.
I was thinking....what if you give the slide a good coat of breakfree or FP-10, then put it in the oven on a moderate heat for a hour+ or so?