Rub the fluff off the quinces with kitchen paper, then wash, peel, quarter, core and cut into pieces.
Cook the peels and cores in a little water in a pressure cooker for about 15 minutes until very soft. Then drain through a pointed sieve and squeeze lightly. Bring the stock to the boil with a vanilla pod cut lengthwise, sugar and apple juice.
Add in the quince pieces, bring to a boil and simmer gently until the pieces are semi-soft, this will take about 5-7 minutes.
Pour the quince pieces without juice into prepared glasses. Simmer the stock for 2-3 minutes more, then fill the jars to the brim with it. Close the jars.