A calm jar! I like that idea.
I'm more inclined to do time in - and give myself time out when i lose it (actually, I wish I could have lots of time out!) But there are times when I just can't handle it and I need to put DS somewhere else for a moment.

I reckon even if they don't seem up to it yet, stick with the explanations and talking things through - give him words to work with for when he can be more eloquent with you. It does get through to them. They are listening. They just lack the ability to do it just yet. Whatever you do say or do, they will mirror it back to you in time. I've been caught out by my son's responses to me sooooo many times. I think - where did you learn that? that's a terrible thing to say.... oh. crap. Just gotta keep plugging away.