Hard-boil the eggs; plunge them into cold water and remove the shells. Stick the cloves into the eggs. Pare the beets, cut them into blocks and boil them in about a pint of water. To this water add the vinegar, bring it to boiling point, add salt, pepper and the celery and mustard seed. Put the eggs into a glass jar and pour over the boiling vinegar; put on the tops and stand them aside for three weeks. A tablespoonful of grated horseradish or a half cupful of nasturtium seeds will improve the flavor and prevent mold.