I would advise careful cleaning of old grease & crud from metal surfaces and bore. I start with Hoppes #9 on cleaning patches. For heavier surface deposits, I wipe the metal (and wood) with mineral spirits on a rag and 'burnish'  dampened metal crud deposits with a popsicle stick. Wood responds well to a wipe down of linseed oil. Once dry, wood likes 'Pledge' furniture polish.

Clean, inspect, and shoot! Don't "REFINISH"! If your Gun Smith advises that, Run Away! Enjoy Patina.

In the old days, the Krag was very popular for Woodland Hunting in Pa., N.Y., Mich., Wisconsin, and many other States. What's not to like? In the late 1920s and 1930s, the DCM sold Krags for $1 and 50 cents, plus postage. (I personally believe, the 'Old Krag-Jorgensen' sold Americans on bolt guns). 

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