Follow your build document for the same steps you used to build production.
You should know where all your code is. You can use the deployment manager to export your configurations. Export customized files from MDS. Just follow the process again, and you will have a clean instance not containing production data.
It only takes a lot of time if your client is lacking documentation or if you re not familiar with all the parts of the environment. What's 2-3 hours compared to all the issues you will run into if you copy databases or import/export schemas?