I agree with what has been posted. Continue to be no-nonsense in your reaction but the key, IMO, is to model what you want them to do in your everyday life, in how you talk about yourself, how you talk around other people and to other people, and give them alternative phrases that are appropriate to the situation. It is very hard to stop one thing if you don't replace it with another.
My mother was such a good mom to me in many ways. She would say all the right things to me to feel good about myself and be proud of who I was. It worked in some ways but what I remember feeling (and an awful lot of how I am) is based on the fact that she herself was terribly insecure and always felt 'less then good enough' in so many ways. Those feelings engulfed her and she couldn't hide it and little kids learn by watching what their parents do, not what they say.
debo5 - it is very very very common for kids to behave poorly when they come home from visits even if the other parent is an A+ parent in every way. The transition is hard and meltdowns are expected. It might help if you establish a very calming routine, where he does x activity, then y activity, and then z activity. Those activities can be anything that is low stress, relaxing, and something that can be very very consistent so it can happen the same way every time he comes home. This was recommended by our therapist and it worked over time. I had to develop activities they did because I have four kids and coming home to just sit around meant lots of fighting usually and one needed quiet alone time followed by interaction and one needed physical activity and interaction. It was kind of tricky but worth it. My little boys were 3yo and if I recall correctly their routine involved snacks, me reading a book, and I think they took a bath.
It also helps if visits are very scheduled and consistent but that is often out of our control.