+1 on Tung oil.
I lightly sand/buff the handles with #0000 steel wool. After sanding I wipe them with a damp cloth and let them dry in the sun for an hour. I like Tung oil. It really brings out the grains in the wood and is not to dark. It's easily applied with a small cloth and wiped on. It holds up real well to sun and rain. If another application is required, no sanding is needed. Just reapply the Tung oil using a piece of cloth. Here are before and after pictures of a handle restored using this method.