Ask Mr. Smarty Plants

Are you sure you even want to grow it? From our Native Plant Database page on Celastrus scandens (American bittersweet):

"Warning: POISONOUS PARTS: All parts, seeds. Low toxicity if eaten. Symptoms include vomiting, diarrhea, loss of conciousness. (Poisonous Plants of N.C.)"

If you still want it in your garden, here are the Propagation Instructions for the plant, which include directions for harvesting and cleaning the seeds:

"Description: Sow seeds in fall or stratify and sow in spring. Bittersweet can also be propagated by root cuttings, layers, suckers, hardwood and softwood cuttings. Treatment of cuttings is not necessary, but it may hasten rooting.
Seed Collection: Collect seeds as soon as the capsules separate and expose arils. Spread fruit in shallow layers and allow to air dry for 2-3 weeks. Remove seeds by flailing or rubbing on a screen. Allow to dry another week. Store dried seed in sealed containers at 34-38 degrees.
Seed Treatment: Stratify for 2-6 months at 41 degrees."

There are several comments on this plant in the Dave's Garden forum on bittersweet. And in case you're not confused enough yet about whether you have invasive, non-native Oriental Bittersweet, or (also non-native) Bittersweet Nightshade, read this Landscaping About.com Bittersweet Nightshade, the "True" Bittersweet.

Common names are always deceptive, and if the "bittersweet" you are inquiring about is non-native to North America, we will have no information in our Native Plant Database on it.

From our Native Plant Image Gallery:

Celastrus scandens