If the corks are new, in a plastic bag, I don't even sanitize them. But if they've been opened a while, I get paranoid and feel the need to sanitize.
What I've done (and it's worked well for me for years!) is to boil 1/2 cup of water and a couple of campden tablets in the microwave in a small glass pyrex measuring cup. (This is the solution that is going into the bottling bucket in a little while). Once the campden is dissolved, and the water is hot, I put it container and all, into a bigger bowl. Do NOT put this near your face, as it's got major sulfite fumes coming off of it. Place the corks around it, and put a lid on the bowl. This sulfite "gas" steams in there while I finish sanitizing my bottles. I then remove that sulfite solution, recover the bowl, and pour it into my bottling bucket. Then, I rack the wine into it and proceed.
I assume that it's sanitizing the corks somewhat, as it works as a sulfite humidor. Maybe it's not, too. But that's what I've done for years and I haven't had one bad bottle yet.