Winter is almost over

Hey y'all. It has been a while since I have been here. Things sorta were slow during winter. Last night I planted some seeds - as winter is almost over and my scullery is warm enough most of the times. I wanna hear from you: I have a couple of seeds from hardy species around here that have a very hard protective layer around them. Someone suggested I use a file to make a chip in the seed? But where? And how big? Is it the way forward?

Here's a good Hard-shell seed prep that applies to almost all seeds.