Wax Prep How Do I Replace A Wax Toilet Flange On Lead Pipe?

How do I replace a wax toilet flange on lead pipe? - wax prep

We are class condominiums east originally built in 1904. My toilet flange newish fled because the bolts on the toilet, the need to replace the rotten subfloor and new tile using a new flange wax. Need to maintain the initial advance sewers. How to prepare the surface? Any general tips for the rest of the wax? No special preparation and ticks in the construction of a new one? What can I tell if lead pipes should be replaced? Open roof from the fund for several days, I want to possible improvements, but I will not be wasted. Included on the Council of the sewage pipes are lead, not the code and are made of steel, rubber. Is this serious?
Any and all help very grateful to all these questions.