Trim removal, '64 Barracuda

What's the best way to remove the rocker trim pieces? Am I correct in assuming the plastic clips underneath them stay fastened to the body? I haven't tried anything yet, figured I'd ask here first before I started breaking clips that I probably can't get replacements for. While on the subject of replacement, the diamond-shaped spring clips (for the trim along the top of the quarters and doors) are rusted. Anyone know if they're available? They don't want to pull out, and I'd rather take a pair of nippers to them from underneath than take a chance bending the trim strips.