assuming you are happy with the color after cleaning thoroughly then by all means recoat. Just this last weekend I cleaned my
UHaul. To remove some stubborn staining I scrubbed the top with bar keepers friend and a nylon pot scrubber, Picture 2 shows the dull finish after a thorough rinse and dry. Picture 1 is after the addition of 2 coats of high traffic Zep to the same area and picture 3 is the trailer