Wash raspberries, removing any stems, leaves or rotten berries.
Transfer clean raspberries into a large, stainless steel stock pot, and heat over low until barely warm. Crush berries (I used a potato masher) to extract juice.
Line a big sieve or colander with several layers of cheesecloth and place over a bowl. I use a big 8-cup marked measuring bowl. Pour mashed raspberries into colander, tie cheesecloth up into a bag, and hang to drip for several hours or overnight.
If you have a really good juicer, scoop remaining pulp out of cheesecloth bag and run through the juicer. Otherwise squeeze your cheesecloth bag on regular intervals to make sure you extract as much juice as possible.
wash out your jars, lids and rings. put jars into canning kettle and bring to a boil. place rings and lids in a bowl of hot water.
Measure your juice, and the pulp you get from the juicer (here's where the marked measuring bowl comes in handy :-) ). You want 4 cups of juice. Add a little fruit juice or water if necessary.
Pour raspberry juice into your large, stainless steel stock pot, and add your dry pectin, stirring the whole time you are adding it.
Place pot on stove on high heat, and bring to a full rolling boil, stirring often.
pour sugar slowly into boiling rhubarb (a second pair of hands is useful for this step!), stirring as you go.
Keep stirring to prevent sticking and burning, until mixture returns to a full boil. Continue to boil for 3 minutes, stirring constantly. Remove from heat when done.
pour jelly into processed jars, putting on lids and rings, tightening to finger tight.
process in water bath in your canner for 5 minutes.
remove and place on a dry towel to cool for 24 hours. Lids should pop down fairly quickly. Enjoy!