aroidgrower

I would nick 10 or 20 till you see some white starch inside. Then soak them for 2 days in warm water change the water daily. I would place them on a heating mat at around 80 to 95f. It seems they respond well to heat. Once sprouted and producing some true leaves pot them up and keep warm 65F 85F. I personally notice any seeds that float are usually useless and dead. Also once the seeds are on the heating pad they should swell up slightly.

I also had some luck years ago with canna musa and other hard seeds that were placed in a air tight plastic container in a greenhouse. A few ounces of water was placed in the container and it was given full sun and heated to around 90F to 120F. Seeds would pop to life daily in this container and would have to be taken out and replanted in a cooler area as well as regular water changes. A seedling left for 3 to 5 days would die in such temps but it did seems to break dormancy for a lot of the seeds.