Nahuel Belich shows how to get rid of Cycles 'fireflies' (white noise).
The last week i run into some white pixel on a Cycles render, i confront face to face the famous Fireflies, so i had to learn what this white dots are and how to get rid of them.
The idea was to do a video tutorial in Spanish but i also did an English version. Please excuse my accent I need to practice a bit more.
The ideas to deal with them are easy, one its using Cycles clamp option, the second its using node compositor to remove them, not by hand one by one, but in a more automatic way.
Also there is a bonus video from Amadeus composition from blender artists that i found two days after record mine, he goes around interesting stuff to also deal with this fireflies and it seems that his English its better than mine. check for this bellow.
Once I recorded both version, English and Spanish, I found a post at blenderarists.org, as i said, from AmadeoCompositions (Aurel Amadeo Gruber) he uses a very similar technique, actually he recorded the video a few months before I did, so i use a very similar technique =^^=, and he has an interesting tutorials that I think it's worth to see.