From
http://www.dollyhair.com/reroottutorial.htm"The first thing that I always do after I finish my reroots with the reroot tool is that I put some Fabri-Tac glue inside Barbie's head and swab it around with a Q-tip. Dollyhair sells Fabri-Tac glue on the "reroot tool" page, so go ahead and buy some if you want to. It's the best glue in the world, in my opinion. It remains soft when it's dry, kind of like rubber, and once it's dry, water cannot affect it. That's an important thing, because synthetic hair needs to be styled with water."