How can you clean burnt on food from an aluminum pot?

Get 2 lemons, warm slightly in palms of hands by rolling inbetween. cut lemons in half, and use a small amount of rock salt, sprinkle rock salt sparingly on cut end of lemon. Scour pan with lemon, dont press too hard though or the lemon will turn to slush! Rinse thoroughly, works on both the inside and outside and is an antiseptic and antibacterial as well as smelling lovely. Also leaves your pots sparkling and can be taken when camping.