Peel cucumbers, cut in half lengthwise and remove core cleanly with stainless spoon. Place the peeled cucumber halves in boiling water for 2 to 3 minutes, cool with cold water and drain.
Cut cucumbers into suitable pieces, layer in jars with enough mustard seeds (do not place tightly). Pour cucumber infusion over cucumbers until canning is covered.
Seal jars tightly, heat to 85 °C, and maintain this heat for 25 min. Next, cool leisurely.