This subject has come up in two Hunter-only forums in the last 24 hours...figured the rest of you might want to know how to do it too: SANITATION SYSTEM: 1. Pump out and THOROUGHLY rinse out the tank to remove any sludge accumulation. 2. Disconnect toilet intake line from the thru-hull (close the seacock first if the boat is still in the water), stick it into a jug of non-toxic potable marine/rv antifreeze, flush it through the system into the tank. DON'T just pour antifreeze down the toilet...that will only protect the discharge and the tank, leaving the rest of the system at risk of freeze damage...as more than one owner has learned the hard way when he discovered in the spring that his bowl had cracked at the inlet fitting in the back of it. Depending on how much liquid is left in the tank, it may be necessary to add additional antifreeze to the tank to achieve the ratio of antifreeze/water needed (see the directions on the antifreeze label) in your climate. Once you've added enough antifreeze to protect the tank, pump the head 50 times to get as much fluid out of the system as possible. After the boat comes out of the water, open all the sea cocks to drain any trapped water...leave 'em open till spring. Do not use antifreeze in a Lectra/San or PuraSan. Follow manufacturers instructions to winterize all Type I and II MSDs. Instructions are in the manuals...if you don't have a manual, you can download one from the mfr's website. FRESH WATER SYSTEM: 1. Drain the water tanks completely (just turn on all the faucets). 2. Drain water heater. Most have a drain petcock; follow manufacturer’s instructions to find it and use it. Remove both the inlet and outlet hoses, and if necessary use a shop vac to be sure of gettting all the water out of it. 3.Connect water heater inlet and outlet hoses together. Bypass kits for this purpose are available from boat stores and RV supply stores. 4. Add non-toxic antifreeze ("the pink stuff") and pump that through the system until all outlets--hot and cold in the galley, head, shower, and any deck wash--run only antifreeze. Leave all the faucets open to make sure there is no pressure in the system.