Too much seasoning?

I had always heard if your soup was too salty just throw in a raw potato and that will solve the problem...never worked for me.

Now I read that if your dish is too salty try adding a bit of sugar or maple syrup.

If it's too sweet then lemon or vinegar will cut down on both too-salty or too-sweet dishes. If the dish is savory you can add a dash of cayenne to cut down on the sugar.

If it's too spicy add something with a little fat like butter or something sweet like peanut butter or honey.

I'd like to know if anyone has had any success using any of these methods.