Don’t forget Source folder too. My project is Blueprint type, and in Source is where C++ files are added when I create one.
I made a backup of the project and deleted all the folders I mentioned.
As a note if someone is doing this, don’t forget it will go through the process of Preparing Shaders all over again, which will take quite some time if the project is big. In my case is something I wanted, and had time to go through that process again.