If your codebase contains anything unused, be it a class, enum, method, property, or even commented out old code, just get rid of it!
Before applying any adavanced programming techniques like OOP, just follow this simple rule. In other words, before even considering being funcy with virtual methods, Adaptor design pattern, or having a religious war over naming convensions, just make sure the code base contain only and exactly the "live" codes. If not, leave the whiteboard there and go back to the desks!
This is a simple programming principle, which is extremely easy for everyone to understand, yet often not being followed up with.