Teleporting items & Vaporizing items

[The chaser]

I need help with two things..
1)
I want to teleport an item every time it's leaving the selected area back inside so it will triger the commands again...I tried some commands but the item stops being usable.

2)
I would like to vaporize any item that touches the acid... I know that there is vaporizing comands in the main story scripts but it is really confusing and i couldn't use it on any other map(Of course with modifications).

Sorry for any English mistakes I made.

For 1 (I don't really know if you can teleport items, but):

AddEntityCollideCallback("nameoftheitem", "ScriptTele", "Tele", false, -1);

For 2:

SetPropActiveAndFade("nameofitem", false, 3);

Play with the values so you get the desired effect.