You can't wrap the pistons - they're inside the cylinder. What you're talking about are the piston-rods, which extend from the cylinder as they operated.
Th first winter after we got our MH, I lifted it off the suspension with the jacks to take some of the weight off the tires. Within a week, there were rust patches on the rods. I polished them out and put the MH back on it wheels.
I contacted the manufacturer of the jacking system about salt air corrosion. They said the piston rods should be fine as long as we weren't "close to salt water". I queried how "close" and they replied "within 60 miles". We're within 60 yards - the homes across the street are salt-water marina waterfront.
I never left the MH on jacks at home after that correspondence. Since we sold it in December, it's not an issue any more. We're officially ex-RVers, with no plans to re-start the lifestyle.
Frank and Eileen
No longer RVers or FR owners