What's best to give sails once a year clean and to get rid of mild rust marks on clews etc

there is a product called aerospace protectorant 303. works great on sails and makes them look new plus provides some uv protection.

it's important to make sure your sails are fully dry before putting them away. storage damage tends to happen to zips and straps. i'd clean zips on your sail and bags very well before storage.

if your in nsw why stop sailing?

Put away for winter? What?

Don't be a summer sailor all year round is the only way!

Where I live, the season starts when it gets cool. Once it gets hot, the wind is dead for two months.

Yeah, rinse/lubricate the zippers especially... I've had sails in storage for years (the small sizes that only see action on rare days) and the only problem tends to be zippers seized or corroded.

Putting some stuff away - use others - I guess a once a year clean

Put away the bigger gear and get out the smaller stuff. Yea!