I found out a new thing to try based on some advice from a wig company. It was to take the tangled wig, soak it in hot water and fabric softener for a couple hours, then comb it out and let it dry! Here are the pics for proof!
As you can see it was... bad. Really bad. That's what happens when you have a cheaper Halloween wig in storage for a few years. Normally I would have taken a look at it and tossed it out. Now way was I going to try to fix that. Well, I wanted to try what I heard, so, one bottle of cheap Dollar Store fabric softener:
...and a sink full of hot water later....
...and 3 hours of soaking, then a brushing out and a drip dry over night I had this:
I also did it to a purple wig to see if it was a fluke. Worked out well. Then I did it to a more expensive one. It worked again! The amount of fabric softener I used was a couple good glugs, about 2-3 capfulls of the stuff.
So, I guess I can say it's a method that does work! You may need to rinse it some after the brush out though, just in case you get carried away with the fabric softener like I did on one wig.