What would you use to wash pretzel hot dog buns?
If you want the hardcore, traditional pretzel flavor and crust, lye is really the only way to get it. You can dip it in a boiling bath of baking soda or washing soda for a minute or so. This can have the downside of giving the bun a really thick, leathery crust like a bagel. Alternately, to do a lye dip, you add one ounce of lye to one liter of water (add the lye to the water, not the water to the lye), stir and give it a few minutes to dissolve. The dough can be dipped in or brushed with the cold lye solution then baked. This will give you the really dark, thin, papery crust with that distinct pretzel flavor.

While the lye certainly isn't a chemical to be careless with, if you obey proper precautions (keep it off your skin, don't splash it, etc) it's nothing to be afraid of either.