Food for thought.
The grape juice bottles are not Toiveled. The manufacturer is not mechuyev to Toivel them because they are merely using them as a means of transporting the grape juice to its consumers, and as such, is not mechuyev Tevila. And for this reason we are not required to Toivel candy dishes and other glassware that we give as gifts to others (think Mishloach Manos).
It is a given that if you wish to reuse the grape juice bottle for other purposes, that you are now using it as an official Keili, and you are required to toivel it. However, as long as you keep on slowly emptying the original bottle, you are not required to Toivel it (otherwise we would be required to empty our grape juice bottles right away).
So, for those that pour Kiddush grape juice BACK into the bottle in order to have them for Havdalla, aren’t you in fact “re-using” the bottle to hold this grape juice until Motzei Shabbos?
Thoughts to keep in mind: A container that keeps food for storage is not required to be Toiveled, however, a container which is brought to the table does require to be Toiveled. (Think sugar dispenser, which needs to be Toiveled, vs. the large sugar container, from which you would pour into the dispenser, which does not require to be Toiveled).
So, let’s hear it, guys!