Replacing main bearings without removing the crank

Somewhere in my archives is a photo of a cotter pin. Stick it in a vise and flatten ring to make a “T”.same idea as a nail.
cotter pin, nail, bolt with the head ground down, whatever works (and just about anything will... LOL). Hoping when they see it, their brains will work and they can grab whatever is convenient and make it happen. :)