to offer a counterpoint, i removed my windshield trim last night in preparation for paint, and was able to complete the job without wrecking any trim or breaking a single clip.
since i'm not replacing the glass, keeping the clips intact and undamaged was imperative. i used a plastic spudger and a 1.5" putty knife, and took it real slow. i started at the corner clips, easing them off carefully because they're made of butter. then i moved to the larger pieces, found where the trim-to-clip grip wasn't as strong, and worked out from there. if you need to do the job without damaging anything, it can be done. just be gentle and don't rush it.
no matter how it goes for you, be excited about the fact that you can thoroughly clean the channel around the windshield. i was stunned by how much dirt, leaves, and other rust-attracting gunk had collected in the 15 years since i last had that trim off.
if you're planning to r&r the windshield, do it right by cutting the old clips and using fresh ones, as others have recommended. either way, enjoy. working on these cars is a good time (most of the time).