Pea family members are so gratifying to sow - up in a couple
of days if you damage them slightly to let the water in.
With big ones, I can hold each seed in my fingers while I
nip very gently with nail clippers.
Smaller ones are not so easy, and I usually rub them between
two pieces of sandpaper. This is a skittery thing to do, though.
Today I had a few medium-sized ones and found a very easy way
to abrade the seed coat. The pumice sitting beside my sink
has an oval indentation. I rubbed each seed in this indentation
with no danger of it shooting away onto the floor.