>>1641052If it's a square-tapered bottom bracket then you need a special tool (pic-related). You screw that into the crank and then turn the other part that gradually pulls the crank arm off.
I don't think you'll do much with a mallet, I tried it only once as a kid with half the family helping (crank had a ripped pedal thread) and we ended up just using a metal saw to cut it at the mounting point as nothing else would make it budge.
As for other bbs can't say much but Shimano usually requires some dedicated tool they make and with SRAM I think it take just a fat hex-key.
