Citric acid is another effective option. Mix about 150 g of citric acid with one liter of hot water and fill the pan. Let it sit for a few hours or overnight, then scrub with a sponge. Be cautious: citric acid can damage natural stone or marble surfaces.
Lemon serves as a natural degreaser and adds a fresh scent. Pour water and lemon juice into the pan, or sprinkle coarse salt for extra scrubbing power. Boil the mixture, let it cool, and then clean with a sponge. Lemon zest can also enhance effectiveness.