Heat is an essential component of many a curling routine, but it's also the cause of all sorts of nasty buildup on your curling iron, including gunky, dried hairspray. Leaving dried-on product on your iron not only mucks up your curl by discoloring and drying out your hair, it can permanently damage your tools. Once you've removed the residue, it's vital to maintain a regular maintenance routine to keep your iron in tiptop shape.
Unplug your curling iron, and allow it to cool completely before cleaning.
Lightly dampen a clean, lint-free washcloth with a bit of rubbing alcohol. Give the entire barrel of the curling iron a wipe-down, applying a bit of pressure to rub off particularly gunky spots. The alcohol helps cut through the product residue. Repeat if necessary.
Create a paste of three parts baking soda and one part water as an alternative to rubbing alcohol. Apply an even coating of the paste over the surface of the iron's barrel, then wipe it clean with a damp, lint-free washcloth to remove stuck-on hairspray. Repeat the process until the iron is clean.
Repeat the rub-down process with a professional curling iron cleaner if you encounter particularly stubborn hairspray. These specially formulated products, available at online and brick-and-mortar beauty supply stores, are designed to cut through and prevent styling product buildup. Typically, you apply them just as you would alcohol or a baking soda paste, but always read and follow instructions provided by the manufacturer to be on the safe side.
Clean your iron about once per week if you use it regularly. If you only curl on special occasions, give your iron a quick wipe after every use -- after it's cooled down, of course.