I think you should consider the jars as part of the present. Could you not transfer to cheaper jars just before you give them? A present "with strings" loses some of its sparkle. In this case, if you don't use it straight away there's the guilt factor that you might think they don't like it, and they have to remember to wash it and return it, it'll probably sit around on a counter collecting dust and annoying them as they wait for the next time they see you.... It's king of on a par with giving a gift that requires a subscription on the part of the recipient, or one that needs batteries without providing batteries. Or taking a meal to someone who's sick/bereaved in several dishes that must be handwashed with care. Unenvironmentally friendly as it may be, giving edible gifts in "disposable" containers is a better idea imo.
If you do continue with the expensive jars and go with the notes, I would word it in a way that stresses the environmental factor: "If you do not plan to re-use me, please return me to Aliantha and help preserve our earth's resources" Twee tough that may sound, it makes it seem more like it's the recipient's choice rather than obligation to return the jar which, imo, makes it more likely that you'll get them back -"Aliantha will appreciate it if I give her this jar" rather than "Oh bollocks, I have to remember to wash the jar and give it back" or "Cheeky cow wanting half of the present back"......
But maybe it's a cultural thing.