It's 30 minutes until the guests show up and you just realised the dish you've been preparing is overly salty! Do not panic -- and save the potato for something else; dropping it in the soup will not reduce the salt. There are some simple solutions, however, to reduce the salt taste, and they take only a little practice to get right. There are also some considerations in keeping the situation from happening in the first place: constantly taste while you cook, read the sodium content on your ingredients, and remember you can always add more, but you cannot take away.
Roll a lemon on the counter under your hand. This crushes the walls inside the lemon, allowing the juices to flow out easily when squeezed.
Cut the lemon in half.
Pick out the seeds or squeeze the lemon through a fine sieve.
Squeeze the lemon juice into the salty dish. Add small amounts at a time and taste the dish to avoid over-seasoning. This method works only if the dish is just slightly too salty. The tongue tastes sour, salt, sweet and bitter; each one balances another. Lemons are sour and counter salt. If you have to put in too much lemon juice, though, it will mask the other component flavours. If there is too much salt use the dilution method.
Pour small amounts of the unsalted stock into the stew, soup or sauce. Stop between each pour, stir and taste for saltiness. You may use water if necessary, but a stock is better because it will not dilute the flavours of the dish as quickly. This method will only work for dishes with liquid as a main component.
Finish with unsalted butter. This will impart a creaminess at the same time as it dilutes the salt. Save this method for sauces or dryer dishes. It can be used on almost any dish. Butter will also help to slightly thicken a sauce, making it a good choice for drier dishes.
Taste the dish after the butter has been integrated. Add more stock if the dish is still salty or too thick.
If there is simply too much salt, you may need to start over; however you can save the main component, such as in a roast. Removing all the surrounding ingredients and giving it a quick bath in unsalted stock, or water if necessary, will wash a large amount of the salty liquids away. Then redo the accompanying dishes with almost no salt at all, or even with a little lemon, will balance out the saltiness.