Chimera's method of popping old seeds.
He has access to a lab obviously but there is great info in there that can be used at home.
"5% bleach in autoclaved, distilled water with a couple of drops of Tween-20 per liter of solution. I sterilize the water in Duran jars (loose lids) in a pressure cooker @ 20 PSI for 20 minutes, and then allow the jars to cool under my flow hood and tighten the lids when the water has cooled. This is probably overkill for most purposes, but it's a variation of the protocol I use for sterilizing explants for tissue culture, and it seems to work with minimal contamination. You can get away with a drop of dish detergent instead of the Tween, I just have the tween-20 in the lab so I use it. If you are going to be doing a lot, you can order a few ml of Tween-20 on Amazon if you like.
First I rinse the seeds in a tight mesh strainer to remove any leaf debris that might be harboring bacteria or spores. These seeds were a little dirtier than most having been field grown, so you definitely want to wash away any superfluous materials. This can be up to a 5 minute rinse in lukewarm water. Cannabis achenes have a lot of little crevices where spores and bacteria can hide, so a thorough rinse is a wise step.
Then I take the seeds and drop them in maybe 100-200 mls of the bleach/Tween-20 solution in an Erlenmeyer flask, but any clean glass vessel will do -the seeds should be fully immersed, maybe 2x the volume of water as seed. You want to keep stirring and swishing the seeds around gently to ensure the current is washing away any contaminants. After a minute of swishing I remove the bleach and strain the seeds from the liquid and start again. No more than 3 minutes total, and if I see bleaching on the small test batch (always do a test batch to seed how the seeds react), sometimes I'll only do 2 minutes.
The next part is key. Immediately rinse 3-5 times (for 5 minutes per rinse) in the same sterilized distilled water (baby water / distilled water from Walmart or the local pharmacy is fine), again using a tight mesh strainer, or simply rinse the seeds in a different vessel with the same volume of water, at least 3 times to ensure the bleach is removed. I use a labratory orbita shaker, but you can do it by hand it's just a little tedious. Once the rinses are completed, soak the seeds in the distilled water as before, for 2-24 hours depending on the age of the seed and the medium you will be growing in. Sometimes I'll use agar plates, but most often I'll just sprout them in paper towels and transfer to a light dirt (like Light Warrior for you Americans) or surface sow on a .peat based planting substrate. You can use whatever medium you prefer, it's not that big of a deal as long as the seeds remain moist." - Chimera
