I tried many different methods in my decades of working with arils and arilbreds, including the one Elm described. Eventually, I settled on slicing only those seeds that did not germinate after going through the non-invasive stratification process that removes the chemical germination inhibitors and makes use of the temperature triggers.
I'll post a few photos of the key steps. The first shows rehydration (a step that can be skipped if working with freshly harvested seeds. In this photo, the viable seeds have sunk to the bottom of the glass while the chaff is still floating on top. Some types will be rehydrated after soaking for a day, some take several days. If the next step is to be direct planting, additional soaking time has been shown to be beneficial. When the next step is stratification, I have not noticed any advantage in soaking the seeds longer.
In a message dated 12/5/2010 10:29:09 AM Mountain Standard Time, email@example.com writes:
I just rec'd my first few aril hybrid seeds. I have Elm's terrific instructions, but I'm not sure if all the seeds with the aril collar actually have to be sliced. Since there's only 5 of each, I don't want to ruin any of them with amateur cutting.