I have a few seeds of Fabaceae trees (acacia cyanophylla, Adenocarpus acutifolius, Caragana arborescens, Cercis siliquastrum, Chamaecytisus peoliferus, Hardenbergia comptoniana, Erythrina crista-galli, Robinia hispida, Teline canariensis)...
I only have a few seeds of each, so I can’t risk losing them by experimenting too much.
From your experience - what is the best way to scarify these seeds (hot water, sandpaper, nail clipper...)?
I don't have any experience with the others, but Caragana arborescens doesn't need scarification. I have a bunch growing by the window right now, in fact. I just picked them from the surface of the snow a mild day in February, when they had seemingly just recently jumped out of the pods. I kept them moist, wrapped them in moist paper, and put them in a jar in the fridge for a bit more than a week (just in case the chill they had got outside wasn't enough). When I took them out of the fridge, most of them had started sprouting. I planted all of them, and most have started growing and look nice. I don't know exactly how to do it with dried seeds, but maybe just soak them for a day or so, and then put them in moist paper in the fridge and check once in a while if they start sprouting?
i don’t have any direct experience with seed of any of those species (though i do with some of their local cousins), but on larger seeds that need scarification, i’ve always used sandpaper or a file.