Hey their chintzgirl,
Cool looking Chrome, and those badges are turning out pretty cool as well.
As you already got a handle on, Those pieces are chrome over ABS Plastic, and the proper way to care for these types of aftermarket Chrome parts is to use a Plastic Cleaner / Conditioner which will restore, or keep the pieces from scratching, and thus keep the parts cean, and clear. Then you want to keep a good coat of your favorite wax on them to protect them from normal wera and tear. A little quick tip that I always do around these types of parts, or door handles, and other areas where their is a straight edge is after polishing them, I like to take a toothpick and run it along the edges everywhere wax, or polish can build up. Your PT is white so wax ans such won't show up as bad from a distance, but you would be amazed if you really go over every detail of your car just how much wax, and polish is built up in cracks and crevices. Unfortunately Plastic / Conditioner is pretty hard to find in stores other than occasionally at like NAPA Auto Parts. Here is a Link to the one Meguiar's offers.
Meguiar's Direct PlastX Clear Plastic Cleaner & Polish
As for the Chrome peeling, I know what your talking about. At one point, some cheaper chrome over plastic can tend to peel over time, but they have made some good advancements within the last several years, and its rare these days to see much of that peeling anymore. In fact, a good example of newer chrome over plastic are your door handles on your PT, and your door spears.
Anyways, I hope that answers your questions.
Go easy, and I will catch you later
Candyman