The best disinfectant for seeds or seed capsules is liquid bleach [6-8% Sodium hypochloride Na(OCl)] or Calcium hypochloride CaCl(OCl) powder, without anyother additives for color, scent etc. The liquid should be diluted to 5% (5 parts bleach to 95 parts water) for sterilizing seeds, whereas for the capsules a 10% solution is good. I recommend sterilizing the green pod, so that you can skip a washing step and most importantly not subject the seeds to the agent. In my experience Mercuric chloride is even better for disinfection, but due to its toxicity it is best to use it only in laboratories which have the right disposal available.