Alan Holmes wrote:

What should I use to clean the edge of the bath before
replacing the sealant?

Clean off as much as you can of the old sealant first using a Stanley
knife blade, then attack the remnants with 'silicone eater' or another
of the proprietary solvents for silicone:
http://www.screwfix.com/app/sfd/cat/...18504&ts=26927

When all clean, finish off by wiping with a clean meths-dampened rag to
remove any final traces of grease before applying new silicone.

David