Ok I admit it! I’m a “basket case” – I love baskets – they corral our “stuff” in an attractive way! It’s hard to misplace a basket! Designate one for each “messy” family member. Direct & demonstrate what you desire, and then dispose (hide from them) everything you find on the floor:). They’ll get the idea & will enjoy knowing where their treasures are!
PS: this works in any “catch all” area