bad cat converter

What is your question?

99 Lexus gs 300 has bad cat converter car has 240,000 mile on it the car still runs great ,what is the cheapest way to repare tihs I ve been adviced that I should take off the cat converter clean it with break cleaner and soak in the water with soap and put it back it should work fine,do I need new gasket or use the one already there ,thanks so much for help