everclear or vodka would likely be the best for cleaning. Essentially, they are one in the same, taking into consideration the alcohol, by volume, is going to be considerably higher with the "pure" grain alcohol as opposed to vodka. But vodka will do the trick, easily. They would be the least likely to impart any sort of flavor to the pipe. If you want to add flavor, at least for the short term, then you would go with whiskey, brandy, run, etc. Understand that by the time you let the pipe dry out, any residual alcohol will be long gone. If any is actually left, and it somehow reaches your lips, it will be far less than what you will consume in eating a slice of bread (which also contains a small amount of alcohol in the natural process of fermentation)