C-SPRAY is correct, I have a spray bottle of diluted muratic acid, keep on there no more than 30 sec after you hose the boat down in this area first, then I wipe dry, and apply silicon, I do this every 4th or 5th time out, but use the silicon everytime back in, sounds goofy but it works for me. Silicon saves my ass everytime, I spray it on everything, Good Luck