I use this method too although on a much more diluted scale. I fill my kitchen sink with hot water and regular dish soap and add about 1/2 to 1 cup of amonia. Some will float right off and others I need to use a razor blade to help unstick them. I do reapply the labels occasionally and will increase the amonia a bit to help them come off easier, but if you just want to remove them without saving them, a little amonia works just fine. Scoring or scratching up the labels before putting them in speeds the process, again if you don’t need to save them.