Wash the tomatoes and carve them crosswise. Add boiling water, rinse with cold water and peel the skin. Cut the tomatoes into large pieces. Peel onion and cut into large pieces.
Chop the apricots finely. Wash and clean the celery. Cut celery and chillies into fine rings. Mix everything with mustard seeds, sugar, vinegar and apricot juice in a pot and boil it down at medium heat for about 75 minutes until it thickens. Stir more often towards the end of the cooking time.
Pour into carefully prepared glasses while still hot, seal well and store in a cold place.