Warning: I tried this and it didn't go well. The chick did manage to hatch, but the yolk hadn't dried and never receded into the abdomen. It only lasted a few hours after leaving the egg.
I'm new to hatching too so all I can say is what I experienced, myself.
I'm concerned the oil make make it hard for the chick to dry after hatching, so keep it to a minimum, if at all.
Sadly, I will say that sometimes the best thing to do is nothing . .
But if you're anything like me you have to try, so here's what I did . .and my "hindsight" thoughts
Wash you hands thoroughly, if the yolk is still outside the chick it could very easily get an infection. If you see blood stop . . . the chicks skin is very thin and easily damaged.
I very slowly (over several hours) picked at the edges of the cracked shell while moistening the shell with warm water (trying not to chill the chick).
I left the membrane alone, because that is like the womb, I did not want to mess with (maybe if I had moistened the membrane, it would've hatched easier, idk)
Remove a few very small pieces and put the chick back to warm up wait at least an hour between attempts. (I rushed and I'm pretty sure that's where I messed up).
I hope this helps and best wishes