1. Remove stems from currants; rinse currants and drain. Rinse and drain raspberries. In heavy 4-quart saucepan, with potato masher or slotted spoon, thoroughly crush currants and raspberries. Over high heat, heat mixture to boiling, stirring frequently to prevent scorching. Reduce heat to low; cover and simmer 5 minutes or until fruit is very soft, stirring mixture occasionally.
2. Line colander or very large strainer with about 4 layers damp cheesecloth. Over large bowl, pour fruit mixture into colander; let stand until 2 cups fruit juice drains into bowl (this will take about 3 hours). If necessary, add enough water to make 2 cups juice. Do not squeeze fruit mixture in cheesecloth, or jelly may be cloudy. Set aside.
3. Prepare glasses and lids, and melt paraffin
4. In same 4-quart saucepan over high heat, heat juice, sugar, and salt to boiling, stirring constantly. Immediately stir in fruit pectin. Stirring constantly, heat until mixture comes to a full rolling boil; boil 1 minute. Remove saucepan from heat.
5. With spoon, skim off foam. Immediately ladle jelly into glasses to 1/2 inch from top and seal with paraffin When cool, cover glasses with lids.