With old diesels, you can pour diesel into the engine to flush it - or even run it for 2 mins with diesel instead of oil - which dissolves crud much better.
Thanks for the video, you could also drop the oil pan and clean all the sediment, or may be add the cheap oil and heat gently with a torch or a heat mat the oil pan to get the most sediment out... Just some thoughts.
On old oil like this, I add 2 cups kerosene then start and let idle (no load) for 15-20 minutes and then drain hot. Then change filter and add good oil. You're done in one step and no wasting cheap oil either. However, don't over use kerosene or any commercial engine flush since the kerosene is an 'astringent' that dries out seals. In my case I've used kerosene in any car only once every 3-4 years and only for a cause like this.
