I cannot remember where I read about this, but it really does extend the life of a berry by a few days or more.
I just pour about 1/4 cup (more or less) of plain vinegar in a bowl and then add 5 or 6 or 7 or so cups of water. Swish the berries around a little to get all the stuff off. I don't even rinse them. I just drain them off and lay them on a dish towel to dry. I even rinse out the plastic containers with the vinegar/water solution.