Striker:
My suggestion is hindsight, kind of critical, BUT I try not to use Magic Erasers. I personally think they are much too abrasive, but you used them. Truth be told, they do have a purpose and place in detailing, but I reserve them as a last-resort method and use them mainly on shoe scuff marks on lower interior door panels that no other cleaning method can remove and, yes, I have scuffed up that plastic.
For cleaning your exterior plastic trim of wax residue, I know that there are car-care product manufacturer`s who make specific detailing products/chemicals for that exact task. But like most hobbyists, you may not have that specific cleaning product in your detailing product arsenal/collection/inventory/stash, so you are forced to use what you do have on hand along with the tools you have.
I find that a good APC like Optimum Polymer Technologies` Power Clean diluted 1:3 and an old medium-to-hard-bristle tooth brush work pretty well as a substitute for removing ingrained/embedded wax on exterior textured plastic trim, along with a little judicious application of "elbow grease" and circular brushing. Does it work all the time? NO! Wax that has been left on by less-than-Autopian-Standard detailers/vehicle owners for a long time will stain the trim plastic and even use of a plastic trim restorer/protectant will not "cover" the stain left behind because the trim plastic color dye has been chemically changed/leached or discolored from the petroleum products used in a wax, depending on the quality and type of wax that was used.
Not exactly the "advise" what you wanted to hear. But in the future, I would try the method I suggested above before resorting to Magic Erasers. The advise about washing the areas scrubbed by the Magic Eraser pads with a good All-Purpose Cleaner (APC) or automotive-safe degreaser soap-and-water seems like very good advice to me. I will have to try that myself on the rare occasions I use a Magic Eraser pad.
And , yes, I have resorted to using a very harsh chemical wax remover (PPG DX-330) designed for vehicle repainting pre-cleaning on a cotton swab (AKA, Q-Tip) and tried to spot-clean an small area by dabbing/rubbing a particularly stubborn wax stain, but the plastic trim became discolored. At least the ugly visual white-wax stain remnants were gone, but now I had a discolored area on the trim. Sometime you choose between the lesser-of two evils; White wax stain OR a discolored trim area.
I do have one Captain Obvious (that`s me) question for you:
What specific trim protectant /restorer do you use on your exterior trim on the `Vette??
If you have some questions about or suggestions for a plastic trim protectant/restore, you can see this linked thread on this very subject:
https://www.autopia.org/forums/car-...faded-black-trim-amp-cladding.html?highlight=