Wigs are plastic, and it's pretty damn hard to damage the fibers with anything besides heat. Regular shampoo, and even dish soap will work just fine on a wig. (Heck, if plastic gets so damaged by shampoo, then why are the bottles it comes in made of the stuff?).
As well, unless you're going to keep wearing the wig heavily for YEARS, washing it a few times a year isn't going to do enough, if any, harm quickly enough to make a difference. I'd only use the wig-formulated shampoo and conditioner for a wig that was going to be worn almost every day.
Originally Posted by Moofingham
There is a vibe here that says "We're in this together! Through thick and thin fabric! Through cold water washes and burning hot irons! Though we might super glue ourselves to our projects, cut holes/gashes/oh-god-mom's-gonna-kill-me into the dining room table, we will stand strong together. Unless there is a 75% off sale at the Fabric store. Then you're on your own. And get the hell out of my way." <3