been preparing the van for newark after winter layup. washed, hoovered, water tank filled and water heater bled through, heating checked ect.:thumb: the last job..........refill toilet flush tank and put chemicals in black tank....ermmm......forgot to empty it after bosworth.oh: i never realised what a good job formaldahyde does, definately no shaking to get the 'jobbies' out. certainly came as a shock when i pulled the tank out. it must act as an anti-freeze as well as we had a few really cold spells but no damage, luckely.