Rinse them quickly in cold water and snip off the stems and green collars under the blossoms. Boil the petals in 2 quarts of water for 3 minutes. Cool and strain, pressing the petals with your fingers to extract all the juice. Measure out 3 cups of the dandelion liquid and place in a large jelly kettle. Add 2 tablespoons of lemon juice and 1 package of powdered fruit pectin (1 ¾ ounces). Bring the mixture to a boil. Add 5 ½ cups of sugar, stirring to mix well. Continue stirring, and boil the mixture for 2-½ minutes. Pour into small glasses and cover with paraffin when the jelly is cool.