I've been on vacation and so am coming a little late to this thread.

My alternatives for removing labels:
- use a hair drier to warm the label and it will let it peel off cleanly
- vegetable oil as a solvent to wash the glue off
- lighter fluid to get sticky glue off, but keep it out of the jar!

I use paper labels and put them on with a glue stick. That glue washes off
quite easily.

Dave