well, at the end of Timecop, Van Damme pushes the young version of the bad guy into the old version of him and they kinds of turn into goop and disappear, because the same matter can't occupy the same space at the same time.
That's one thing that turns me off to the whole idea of PHYSICAL time travel. Matter is neither created nor destroyed, yet if you have the same matter in the same time-space location in two different locations, you have added matter to that time-space location, which we know is impossible to do.
I think the closest we'll ever come to actual time travel is cryogenice freeze