Keep them away from all television and homeschool them. It used to be neither were necessary, but currently the Marxists have achieved their long-sought goal of the raising of children by the state - state-schools and television both pump them full of lies. I'm only 21 and even I can look at my elementary schooling, and what's going on now, and say "at least I didn't have it this bad".
There are a few movies that are fine to watch of course, but they are few and far-between. (Braveheart, The Patriot, Spartacus, to name a few.)
I'm not just saying this as an easy-out. There are so many traps designed to catch children...it's almost unreal-seeming. Love fire too much? Pyromania, psych diagnosis to follow them for life. Like fire too little? Pyrophobia, psych diagnosis to follow them for life. Mandatory Jungian or Freudian (or both) psych testing disguised as 'employment-aptitude-testing'. Television no longer hides the symbolism of the jews - it plasters it in plain-sight for all to see, gleefully rubbing our faces in it.
http://www.youtube.com/watch?v=V4zz_EThJcYThere is no homogeneity in any cartoon at all on television anymore. Not just a little of it, but none whatsoever, so that the notion of a homogenous racial culture might be removed from the minds of the young. Darwinism, Nietzschiesm, and Marxism are taught full-force in every class-room, written in-between the lines of every school-assigned book and in the subtext of every school-assigned movie.
To give you an example, in 11th-grade history class, we were comparing the Only Two Systems of Economics (tm), Capitalism and Communism. The teacher, we'll call him Mr. Taylor, asked the class "...and why doesn't Communism work?"
Nearly all of the class replied, in near unison recollection of an earlier lesson, "because humans are too greedy!".
So yeah, sorry for the bit of the ramble there, but please....please keep your kids out of public school.
That being said, sometimes this isn't possible, and public school is a necessity (where most race-mixing is learned, outside of television). The answer is usually simple, though, and only very extreme circumstances can undo this: be there for them. Don't be a part-time parent, but always be there when they need you. Don't follow the false line of "well, I'll just let him do his own thing and step in if things go amiss". No.
A family who love each other, and the children of that family, who are raised, truly /raised/ by their parents rather than plopped in front of a tv or told to 'go play' for years on end will overcome any attempt at racial mixing by our adversary.