Any tips for removing broken bits of glow plug harness from 6.0 powerstroke without removing valve covers?

So I was switching out the glow plug harness on the driver side of a 2003 6.0 liter engine (it’s a 2006 body, don’t ask why). Looking back, I should have removed the valve cover and oil rail to do it. Anyways, there a few bits of plastic left behind, and I figure I should remove them before running the engine. Does anybody have some tips for getting those suckers out of there? I tried using a vacuum cleaner, but no luck. At this point, I figure I need to open up the valve cover, but if anybody has some advice, I would appreciate it.