Originally Posted by jkath
I know that if you add potatoes to over-salted it helps(
This is actually a food myth that has been proven to be incorrect. For a good read check out What Einstein Told His Cook by Robert L. Wolke.
is an article which shows the scientific experiment that he conducted and the results he found. Very interesting stuff.
With salt, and I would say pepper or other spices as well, for the most part, the best way to reduce the amount without affecting the integrity of the dish is to make up another batch without the offending ingredient or at least a lot less of it. Then combine the two.