I've mentioned this on other threads, but I've used both methods quite often. I still think salt may work better, but I've preferred the cotton balls lately. Both are easy to clean up, cotton is easier. Just make sure there's no salt hiding in your shank if you do the S/A. The dropper is essential in my opinion to keep the alcohol from getting on the finish, unless you plan to refinish the stummel anyways.
The activated charcoal/oven method seems to work well too. I had some good results on a few estate pipes I tried it on. Right now I'm experimenting on one of my own heavily ghosted (Blue Note and Argosy Black!) pipes by filling the bowl and an old margarine container with activated charcoal and leaving it with the lid closed for a few weeks. It's the toughest ghosting I've ever worked on, and I'm the only owner of the pipe. 8O Once I decide to pull it out, I'll post the results.