Soft-centered seedpods often contain germination inhibitors, which means you have to wash the seeds really, really well if you expect them to ever sprout. I learned a trick for doing this in my propagation class that makes seed-washing very easy.
Once you've collected all the seeds, put them in the foot of a nylon stocking and tie a knot in the end. Hang the stocking over the edge of the toilet tank with the the foot of the stocking containing the seeds dangling in the water. Put the lid of the tank back on to hold the end of the stocking securely in place. Every time you flush the toilet, fresh water will rinse the seeds. After a week or two, the germination inhibitors should be leached out and you'll have clean seeds to sow.
Linus the cat inspects my work.
Following the advice of various sources on the Internet, after the seeds have been thoroughly washed, I'll sow them in some potting soil, cover them with vermiculite, put them somewhere warm, and keep them in complete darkness until they germinate (30-60 days).