If what is suggested doesn't get you results try using Prep Solvent like you use to remove wax, silicone and such before you paint. It will take the wax off but usually gets the white lines off the rubber and trim. It will also take any road tar off. Like suggested a tooth brush will speed up the process. When applying wax keep back from the trim and rubber a little and when you wipe it there will be wax moved to the area not covered. The best wax I have ever found was developed for Marine use is Collonite. It is pure carnauba wax and soap and water will not wash it off and goes on easy and last forever, no chemicals just wax. One can lasted me for years and years. Don't have a can handy to get the number. There are several but one works much better than the others. Can send you the number if you PM me tomorrow.
David