craftgrrl | Getting food scent out of glass jar

Hi!
I have searched the memories and google for this but I cannot seem to find what I am looking for.

I am trying to start a small business where the three R (Re-use, recycle, reduce) will be the stars. As I plan to make natural beauty products (among other things), I do need some packaging. I thought that re-using all the glass jar I use in a year would be a great idea. Unfortunately, most of the jars smell very strongly like their previous inhabitants (jams, pâtés...).

Do you have any idea how to remove the scent from the jars? I have washed and washed them and the smell doesn't seem to fade.

Thanks a lot!

And so this is not text-only, here are some scarf I stenciled for my male friends last Christmas.