Kim,

Hi, I am actually a detailing freak and spend a lot of time cleaning, polishing, waxing and the works. I do get wax on the trimmings of my car as well. I know of 2 ways to deal with this:

1) This is a preventative way and it involves using 3M painter's tape which is tape used to cover the places where you do not want "painted", in this case, places where you do not want waxed. I have not tried this as I think it involves a fair bit of work lining all the trimmings on the car

2) Use Meguiar's Gold Class Trim Detailer. I apply this using a cotton terry cloth and where the wax has hardened or got stuck into the little gaps, I merely use the edge of the cloth damp with the trim detailer and rub with some pressure. It restores the original colour of the trim/bumper as well as protects against the weather/continuous washing. also gives it a like new appearance. My preferred way as it makes the black trimmings shine besides getting rid of the wax residues

Hope this helps