Is it possible to REMOVE a line from the properties list?

I have no trouble editing existing lines...but sometimes I want to take something out.

If you mean the "Attack Bonus", "Defense Bonus" etc item properties then yes it is possible ... Providing you are using KotOR Tool just open the item properties window, click on the empty rectangle before the line you wish to delete and press "delete" ...
If this is not the case then I'm sorry I can't give you an answer for I don't completely understand the question ...

Ahhhhh...so simple and obvious. :p

I was looking for a menu option. hehe