Don't get me wrong, science is cool, but how do I remove projects I don't want? In BOINC Manager, I see my list of projects. Random ones keep popping in and I don't know why. In Project Commands, the "Remove" option is grayed out for the ones I want to remove.

I am having the same issue :(

On the site here you can choose your computing areas. You can change an area to 'Never' but you do not have the ability to turn off work units by project. Someone can correct me if I am wrong but I believe this is by design to help keep it as simple as possible. If you want more granularity you will want to look into another manager.

They'll get automatically removed after a while if you choose never in the science areas configuration on the site