What is the purpose of a drain cleanout plug and how can it be effectively used to maintain a plumbing system?

The purpose of a drain cleanout plug is to provide access to the Plumbing system for cleaning and maintenance. It can be effectively used by removing the plug to clear clogs, inspect the pipes, and prevent blockages from causing backups in the system. Regularly using the drain cleanout plug can help maintain the plumbing system and prevent costly repairs.