And I forgot to look...
Anyways, I don't know if there is a way to clean the corks. I would think a winery would have a problem with competitive corks, or at least I haven't heard of it. If they did I would tell them to give me their corks then and I would gladly use them.
If you want clean corks I would look on Ebay. Also, Pottery Barn is selling bags of decorative corks. I don't see them online, but I saw them in the store this weekend. I'm not sure of the price, but you might be able to buy the pre-made ones for the same price.
You could always use the used wine corks in other decor also. Like hurricanes filled with corks. Or make trivets to use a on buffet or station. Possibly tie them in to cocktail hour centerpieces. Just some thoughts.