It may be worth trying the methods on the wiki page above, then?
I actually don't really mind if labels stay on for re-use.
Mind you, I saw someone selling (or trying to sell) used Bonne Maman jars on eBay a while back, so might be worth doing
(Ditto La Fermiere ceramic yoghurt pots...)
“In the midst of winter, I found there was, within me, an invincible summer." Albert Camus