Here's what I use...
1) Clean blade using Break Free or similar gun clean/protection products lightly. This will also help remove surface rust, etc.. Idea is to not scratch up the blade, be gentle. Some folks also use an antler in pitted areas.
2) On leather grips and leather scabbards, I use Pecard Leather Dressing. I don't use anything on the shark/rayskin grips.
3) Finally a light coat of Renaissance Wax on the blade.
4) I store them all in a glass display case. Cuts down on dust. Also, store them outside of their scabbard. Every few months I dust off and check them up close. Try to keep your fingerprints off the blades.