Put it away, or I'll take it away

My mantra in class. Confiscated yet more work from those little rotters in 5/5 today, and refused to give it back until they asked me nicely in English and apologised. And even that was being far too lenient. I get so cross with them doing work for other classes in my lessons - and worse, thinking that I can't tell. Come on, it's easy to see it's not English work because it's in Thai! If I have them next year (which I will if I keep the same classes as I have now - I teach all of M6) and they continue to do that in my classes I'm going to keep it for a week and serve them right if they get into trouble with their other teachers (let them do the discipline, since the kids clearly have no respect for me).