"skuffing" seeds is where you rough up the surface of the seed, with sand paper
or a nail file. Theres like a coating on some of the seeds that doesn't let water through.
H2O starts the germination process. No H2O no germination.
thats why you soak your seeds in a cup of water for 24- 48 hours. The seeds that fall to the bottom of the cut have taken water and are now ready to be put in your moist paper towel. The seeds that are still floating either have to much water tension to sink. take your finger anf poke them down in the water a couple of times to get the whole seed wet. Or the seed might need to be "skuffed", Or the seed is a bad seed.
Remember warm and dark, about the same water temp as cloning about 75 - 85F