Just leave them where they land, then when she runs out of things to wear, show her how to put them in the basket, and then in the washer, girls are worse than dogs, because dogs can be trained a lot easier.
embarrass the crap outta her. pick up all her dirty underpants and one day pick her up from school..play the crazy mom part waving around her underwear for everyone to see..then ill guarantee you that she wont ever leave her clothes on the floor
That would be very embarrassing to her. I would take her down to the floor and rub her face in her panties. I do like your idea too.
This is what I do when my kids do this. Take all the things she leaves out. Place them in a paper or plastic bag and hide them. When she asks where they are, tell her you have them. If she wants them back then she has to do one of two things. She can either clean the bathroom or house cleaning of your choice or she must pay to get them back. This worked very well for me after my kids had to work their asses off for their shoes etc back or pay me a ton of money! I bet she'll catch on pretty quickly. You may want to store these things in your trunk of the car as she will tear the house up looking for them and may find it thus you are defeated!My kids tried this bust I was one step ahead of them. They no longer do this. Just a thought.Good luck!
Some of the ideas already suggested are sound.
On the other hand, she's obviously challenging you.
This sounds mean, but you have to be the ruler of your roost.
Let her know that she can either follow your few sensible rules or find another place to live.
Use all the old fashioned punishments: no phone, no tv, no friends, no freedom until the chores are done. If she mouths off, slap her face. Seriously, don't fuck with mom.