use an adjustable spanner but also a very thick bolt and nut(and possibly a washer) to hold the spanner against the bb cup or it will just keep slipping. hit the end of the spanner with a mallet, anticlockwise for the left cup to loosen, clockwise for the right cup
use an adjustable spanner but also a very thick bolt and nut(and possibly a washer) to hold the spanner against the bb cup or it will just keep slipping. hit the end of the spanner with a mallet, anticlockwise for the left cup to loosen, clockwise for the right cup