As DaveR says.
I would also note that if you turn off hidden geometry in a “scene” that you save the scene (right click tab to “update”) so that each time you return to the scene, the hidden geometry does not return. Also make sure the “hidden geometry” box is checked in the scenes dialogue box to be sure this option updates.
Not sure if some of the lines are coincident but you can also get rid of the “guides” in the background too in the same way.
One more thing to note from my own experience, is that occasionally we end up with a solid line in the model that we don’t necessarily want to be visible, but the model still needs the geometry the line creates. In this case you can “shift+eraser” tool on the line, which make the line invisible in the view but does not delete it. Like above, you then need to “update” the scene to save that look and prevent the line returning next time you look at that scene.