Wash and dry the plums well. In each jar, put in 1 tablespoon salt, and 1 1/2 tablespoons sugar, vinegar, 2-3 cloves of garlic, a few black pepper and allspice grains and a few sprigs of dill (or celery).
Fill the jars to the brim with green plums and top up with boiling water. Close the jars well with caps and turn them upside down. Turn the jars over periodically over several days.
Then store the green plum pickle in a cool, dark place.