Fill a stainless steel or dutch oven with water and blanch the rhubarb in boil water for 1 minute. Drain but keep fruit heated in a covered bowl or pot.
Combine sugar, Clear Jel, and water in a pot stirring on medium heat until mixture thickens and begins to bubble. Add lemon juice and boil 1 minute, stirring constantly.
Fold in drained rhubarb immediately and fill 1 quart, hot jar, with mixture, leaving 1 inch headspace.
Remove air bubbles and adjust headspace if needed. Wipe rims of jars with a dampened clean paper towel. Install hot lids/rings per manufacturer recommendations and process in water bath canner for 30 minutes at a full rolling boil.