This trick comes from the USSR, but even modern housewives sometimes use it.
In the old days, if you looked into the oven of a Soviet housewife, you could discover an interesting detail: at the very bottom, on the baking sheet, there was salt, yellow or brown from soot.
The product could have been there for years. No one would have thought to throw it away after the first use.
Salt in the oven had its own simple purpose. The essence was to bake the dish evenly.
The problem was that the heat was distributed from top to bottom. The baked goods were burnt on one side and remained raw on the other.
To prepare the perfect dish, a baking tray with salt or sand was placed in the oven. The three-centimeter layer absorbed the heat and then released it evenly. This way, the dish was baked well on all sides.
Some housewives did not use sand or salt. They had bricks or stones for this. The essence was the same.