copper and brass surfaces

hi all!! i have a job as a matainance supervisor in a complex thats been around for 60 years i was replacing a toilite piping with pvc and the old piping is 3inch copper 4ft long with a brass filange and elbow ,it has wax build up on the filange from the wax ring and the copper and brass elbow has black stuff on them my question is should i use a surface grinder to remove all the black from the copper pipe and bring out the shine? same goes for the filange and elbow.

thanks any help or advice would be greatly appreciated