A Reddit user posted on the subreddit /r/hardwaregore (which is home to hardware mockers) how he used a 4kg copper block as a passive cooler for an Intel Core i9 processor, Tom's Hardware reports. Unloaded, the processor's temperature held at 35°C, quickly reached 80°C under the stress test. When the stress test ended, the temperature returned to its previous values within 10 seconds.

As the user points out, the unit was once a component of some medical equipment, where it probably acted as a cooler. The holes drilled on the sides are threaded, apparently to add liquid cooling. It is not known if the user will further experiment with the unit. Also, unfortunately, he did not provide details about the experiment, and he himself recommends treating his experiment with "skepticism."
Earlier, an enthusiast from China unveiled her "crazy" CPU cooling option. She tested the iron outside at temperatures as low as -53 °C. As soon as the temperature dropped to -40 °C, the liquid in the 360 mm cooler for the CPU froze. Instead of the cooler, she installed a NH-P1 heatsink from Noctua and constructed a huge air compressor from dozens of fans.
Another enthusiast used potatoes, cheese, ketchup, toothpaste and baby cream as thermal paste for the Radeon R7-240, testing which of these will cool better. According to the test results, only half of the "thermal pads" handled the load. With the rest, the temperature reached 105 °C, after which the trotling (clock skipping, an overheat protection mechanism) started.