Fixing foods that are too salty is either very simple or simply not possible, depending on the type of food being fixed. There are options available for liquid-based foods and solid foods. Be willing to change the dish to something different if necessary. Add a sauce to cover a serving of casserole even though casserole doesn't usually take a sauce. Be prepared to take some bold but careful steps to fix over salted foods.
Add more of the basic ingredients to the dish you have prepared if the dish is liquid-based. Make certain the additional broth, tomato sauce or vegetables are sodium-free. If the dish is a solid one such as meat loaf or fried meats cover it with bland, no-sodium gravy.
Pour a small amount of white vinegar into the stew, soup, gravy or other finished liquid-based dishes. Taste the dish every time vinegar is added to determine if more is needed. Continue adding white vinegar until the salty flavour is tolerable or until the vinegar flavour becomes too strong.
Mix an equal amount of granulated sugar to vinegar and add it to the dish. Continue doing so in very small amounts until the flavour is acceptable or until the flavour is becoming too strong with vinegar and sugar.
Cook a salty ham basted in white vinegar to cut the salty flavour. Add just a small amount of sugar to a salty, sour or bitter dish to mitigate the flavour.
While it is a safe procedure to add more of the basic ingredients of a dish to dilute the salty flavour, be careful when adding vinegar or sugar - add only in small increments at a time.