Hi - What ever is used to put tiles up - inbetween where the tiles are on the wall and where they meet the top of my bathroom sink (space of only a few millimetres) - it is cracked - it is hard yet there is a slight softness - as if at one time silicone or similar sealant was applied over it - whatever it is - and is getting murky, mouldy where it has cracked - what do i need to do to clear this up? Thanks Becka