Lay your sails out on the lawn and wash them with warm, soapy water. Dry them well before folding or rolling them for storage to prevent mildew. (Click here for more on canvas cleaning and storage.)
While you are cleaning the sails, check for signs of stress at the corners, torn stitching, and delaminating Mylar. Look for areas that may need a reinforcing patch. If you find any problem areas, take the sail to your sailmaker early. You may get a better rate if the work is done over the winter, and the sailmaker will certainly get busier as spring approaches. The sailmaker can wash and check your sails if you don't want to do those jobs yourself.
Most yards leave the rig in for the winter, but some owners prefer to pull it. Removing the rig will reduce stress on the hull caused by winter winds while the boat is on the hard. Also, it's easier to inspect the rig when it is out of the boat.
To check your rig, first tie a messenger to the halyards and pull them out of the mast. Rinse them, along with your sheets and guys, in a bucket of warm, soapy water to get rid of the salt. This will make the lines softer and easier to handle next season.
Start at the top of the mast and look for worn sheaves, elongated holes or bent pins in shroud terminals, and missing or broken cotter pins. Remove and check any padding on spreader ends. Remove the wind indicator and spray electrical fittings with CRC or a similar lubricant. In the spring you might want to change light bulbs at the masthead to ensure that the navigation lights will work all season. Also, look for cracks around halyard exit openings and check the base of the mast for corrosion. If you find any, it should be treated before it has a chance to spread.