T.,
First, the good news....they do outgrown it!!! My son was a bear to get to pick up his toys when he was younger now his room is nearly spotless and he yells at me if I leave my shoes where I kick them off. He is 17.
I can't actually take credit for him learning that behavior, it was my Army (now retired) husband that deserves all that credit!! :-) I give it proudly. I want to explain that when I met my husband my youngest son was barely two. I was a widow with three children (8, 4, 2). He did a wonderful job loving my children as his own!! when he had four of his own already!!!
He would do as several of them suggested, he gave my son a certain amount of time to pick up his toys. After that time was up if my husband went in his room and his toys weren't picked up, my husband usually put him in time out in the room where he had to look at the toys that didn't get picked up for a certain period of time. Then my husband would go in and my son would have to explain why he left those toys on the floor and what he was going to do to correct it. He would give my son a chance to get the "rogue" toys picked up. It didn't take long before "all" the toys got picked up so he didn't have to sit in time out....he hated time out!!
I don't know if that would work for your boys, but their punishment should be instant so they associate it to the crime (not getting the toys picked up). Taking away privileges like desserts and TV for a week might confuse them because it isn't related to the "crime."
It's funny, as I am typing this my son goes, "Mom, I have got to clean my room!" LOL See! There is hope!
I hope this helps a little!!! :-) I never had twins but always told my son he was my twins because he had the energy of two!
Good luck on training your boys and on your degree!
N.