Wire harness...Clean or New?

hello, after a 3 year stall in my project I am back to it. its a 70 dart swinger one owner. The engine bay is painted and I put the 340 in. I am working on cleaning up some of the various parts and the engine bay harness is next. It is very original with not splices or cut. it has the original tape on it. is there a product used to detail these harnesses or do people re tape it. or even buy new? any help would be great,
thanks, Joseph Moy