hey boat owners..just passing on a little info learnt while grooming my M26. I watched others using high pressure equipment trying to get a good look on their topsides in the NYS marina. I used cleaning white vinegar (grape juice) ($3 a big bottle from woolies/IGA) sprayed on with a $2 plastic spray bottle and it worked a treat..got rid of that ingrained black stuff by killing it then hosed it off. Takes all of five minutes to spray the boat. Inside I sprayed it on nooks and crannies and especially on cloth that had these black spots...killed ?m dead cloth came up like new. A watered down bottle of spray and I did the lot inside...just left it mainly and no return of mould after 12 months...marvellous.