dmcdivitt's helpful comments under this original at Lifehacks SE inspired this post. I indeed am awaiting his/her unification of his comments to answer this question her, for the benefit of others.
Probably due to old age, the screen of my old Sony SDM M51 monitor flickers. The Sony representative advised that inside the lower left side (hereinafter abbreviated as LS) of the monitor (as depicted in red above), parts nearing the front of the screen have loosened from parts at the back. So the only solution is to clench, grip, or squeeze the front and back of the red area (eg by hand), which has eliminated the flickers for the past years. Alas, the detachment worsened a few days ago, to the extent that my hands hurt and the LS now needs continual compression and grasp to stop flickering.
So what can I use to resolve this problem? I tried a large binder clip which only works when my hand clings to the clip; as soon as I stop holding onto the clip, it flings itself off because the LS is too thick.
Footnote: Please advise on other words to describe this problem (I struggle to find the perfect diction). Here is a sample Google image search for what I believe the problem is.