I received the following task
- Remove the nuget packages from MyProject (check other webapps):
<add assembly="Microsoft.Web.Samples.ImageSprite" namespace="Microsoft.Web.Samples" tagPrefix="asp" />
Since they are NuGet packages you should just be able to go to tools->NuGet Package Manager -> Manage NuGet packages for solution.
This will list all the installed packages for the project and you can uninstall them from here.
EDIT: Alternative solution from OP That seems like a solution, but I already found out another one. I needed to remove the corresponding lines from packages.config