4. Cook Rapidly: For quickest jelly making, use an aluminum kettle or saucepan—6 to 8 quart size. The kettle or saucepan should be less than one-half full of sugar and fruit to permit a full rolling boil, a boil which cannot be stirred down. Use hottest flame. If fire is slow, keep kettle covered after sugar is dissolved until mixture comes to a boil. Stir while coming to a boil, and while boiling.
5. Add Certo: For jelly, add Certo as soon as fruit juice and sugar mixture comes to a boil; then bring to a full rolling boil and boil hard for exactly ½ minute, stirring constantly. For jam, cook fruit and sugar mixture at full rolling boil for exactly 1 minute, stirring constantly; then remove from fire and stir in Certo. Time boil by the clock.
6. Skim, Pour, Paraffin: Skim jelly and pour directly from saucepan into clean, freshly scalded glasses. Skim and stir jam for 5 minutes by turns. This cooling helps prevent floating fruit. Ladle into glasses. Leave ½-inch space at top of each glass. Cover at once with ⅛ inch of hot paraffin. When cool, cover glasses with scalded tin covers or tightly pasted paper covers. Be sure to store in cool, dry place.
New Certo Users: Read carefully pages [4], [5], [17], [18], [31].