Are you tired of stabilizing your trailer and destabilizing your hands with rust? If so, here's my mini-mod of the day for those who use these aluminum jacks: Hacksaw the handle/rod off. Get some 5/16" rod of stainless steel from your friendly neighborhood hardware store. Pick up some 5/16" S.S. acorn nuts while you are at it.
Cut the new rod in 7" lengths. Cut (or have someone cut) about half inch of threads (again: 5/16") on each end.
Sand off the rust above the larger main column threads. Coat with that red Rustoleum stuff, recoat with gloss black Rustoleum (by this time you have probably cleaned the threads with a stiff brush and some paint
thinner, I hope). Wait until the paint is dry.
Slip the new rods into the shaft and tighten the acorn nuts. Put some marine style grease on the threads and your're good to go. No more rust on your hands.
(Or, just wrap the handles in duct tape.)