I used to insist that my kids clean up by themselves, and we had many standoffs on the topic. But then I read that the important thing is to get the kids cleaning... and that it's ok to offer to help out if there's resistance.
Since then, I always ask the kids to clean up their toys... and if they balk, I offer to help them and we do it together. I"m surprised at how effective this has been! Once they get started cleaning, they usually finish on their own... even if I'm not helping much or at all. Color me surprised!
Do you help your LO clean up after they're done playing?