Originally Posted by Bianchigirll

It would help to know what kind of bike you have and if the bottom bracket (BB) has any threading markings on it

36x24 would be Italian and regular right hand thread (righty tighty / lefty loosey)

1.37x24 is English, the nondrive cup is right hand thread but the drive side (AKA 'Fixed Cup') is left hand thread so you need to turn to the left to loosen.

If there is anything different marked on it post the numbers here and somehow will know the threading.