Break Free CLP and a piece of a terrycloth towel. Spray on the blade and let it sit for a few hours, then spray on cloth and rub the blade to get as much of the rust off as possible. Wipe off excess and let it sit overnight then put back in sheath. I do not know what can be done to the sheath to keep it from deteriorating without destroying the value.
Just rub it down with CLP.
Rub a little saddle soap on the leather handle and the sheath.
RESIST THE URGE TO GLASS BEAD! RESIST THE URGE TO PULL THE LEATHER RINGS OFF THE HASP.
DO NOT USE SCOTCHBRIGHT! Take a piece of heavy canvas and rub the thing with CLP. Dirt and grime will fly away, and the original piece will shine.