You just have to be very patient. After seeing several of these cracked in the junkyard I realized this. I haven't yet taken mine off (to replace the leaking valve cover gasket), but I practiced on one at a junkyard first...then bought it when I successfully removed it, just in case I crack my own. You just have to baby it. Get something thin (blade) and run it along the opening/crease. Then get a flathead screwdriver and work every angle you possibly can on between the head and valve cover...using ANY possible leverage point you can find. This should (hopefully) only take about ten minutes of working it. Eventually you'll get one corner to pop up just a bit. Then you can stick your screwdriver head in there and carefully use IT for leverage when you pry up the other side. Of course, you'll have to be very careful not to ding/score any part of the head with your screwdriver. Good luck & have fun!
Hmm... since you're just after the cam, will the yard charge you for a dinged head/broken valve cover?
I just checked my manual: it just says, remove the nuts, then the cover. No secret handshake required.
Want me to ask specifically about the XFi cover on teamswift?
If you want to ask, that would be great. I only had a leatherman and a few different sockets with me yesterday, so I was unable to really work hard on it. If I have the time today I'll go back with a prybar.
As for the damaged valve cover, they could care less. I only get charged for what I buy.