Meshes won't go away In this project: https://www.file-upload.net/download-12514827/broken.blend.html

there are a lot of meshes which won't go away by selecting them and pressing X, aren't selected after selecting by Type and don't even get removed by my program. Why? My only bet atm is to manually rightclick them and delete them one by one, but that can't be the only way, right?

Btw this was the program which hadn't worked:

for ob in scene.objects:
    ob.select = ob.name.startswith("VBar")
bpy.ops.object.delete()
Your meshes are on different Layer. Select it or add it (the Layer)
by Shift+MouseClick and you will be able to select them.
If you don't see them - as they are just simple lines; press Z to go to Wireframe Mode.
For Python solution go here: Get the list of objects on a layer in python