I'm going to make some mint sauce to use up some of the mint in the garden.  I want to make it to store and found a recipe for storage by just googling but I thought I'd see whether anyone else has done it / has a better recipe.

Basically this one says chop up your mint, and tap it down till it's level in a measuring jug.  Pour in twice that amount of white wine vinegar.  Add 1 Tbsn sugar for each 150mls and dissolve.  That's it!  Then when you want to use it you dilute the concentrated mixture with a couple of tspns of vinegar to each tspn of the mixture.