In keeping with the general rule that mitzvah objects, including comestibles, be discarded respectfully (as well as possibly baal tashchis), how should one get rid of leftover kiddush wine? It's not as easy as bread to put into a double-bag and kiss. The first link suggests that even less than a kezayis of bread must be discarded respectfully, so I'm guessing less than a revi'it of kiddush wine must be respected, too. But how? Assume I don't want to drink it now or later.
Actually, (based on a Gemara) the Kitzur in סימן עז - דיני הקדוש והסעודות בלילה וביום states that one is supposed to leave over wine from the night Kiddush to the morning one, and for the morning for Havdala.
סעיף ז' הַכּוֹס צָרִיךְ לִהְיוֹת שָׁלֵם וְנָקִי. וְכָל הַדִּינִים שֶׁהֵן בַּכּוֹס שֶׁל בִּרְכַּת הַמָּזוֹן (לְעֵיל סִימָן מ"ה סָעִיף ג' וְסָעִיף ד') יֵשׁ גַּם בַּכּוֹס שֶׁל קִדּוּשׁ בֵּין בַּיּוֹם בֵּין בַּלַּיְלָה, וְכֵן בַּכּוֹס שֶׁל הַבְדָּלָה. וְטוֹב לְקַדֵּשׁ בַּלַּיְלָה עַל כּוֹס גָּדוֹל שֶׁיְשַׁיֵּר מִמֶּנּוּ לְקִדּוּשׁ הַיּוֹם וּלְהַבְדָּלָה.
To answer your question: One either leaves it in a covered vessel, or one pours it back into the bottle. Either way one has to make sure it is not "Pagum".
Pagum: Wine that is unfit for Kiddush because somebody drank from it already.
Make sure it is not "Pagum": (1) After drinking from it, one adds some wine to the leftovers (and pours it back into the bottle). (2) One doesn't drink from the Kiddush cup; rather one pours some wine into another cup and drinks only from the second cup.