depends on what is there, i'd guess.... is there crud built up? old caulking? a plastic scraper and some bleach may be all you need. a plastic scrubby-pad would help too. but that depends on what you have there too.
Caution: any advise taken from me can cause brain damage, hearing loss, and 'limbs falling off' syndrome. Check with your Doctor before taking any advise from me. Po)