[ithacaartist]

Boiled linseed oil was the original unless I am mistaken, but any fairly light oil type finish will be fine--Danish oil, Brazilian rose oil, etc. Although also a good finish, polyurethane is avoided by many collectors. The darkening, or patina, consists of stuff that permeates the top, visible layer of the wood. Dirt and oils combined, mostly. I'd try to gently remove as much dirt as possible physically. Organic solvents will remove the oils and a little more of the microscopic crud.

A pair of grips can be made to look virtually brand new by chasing the checkered pattern with the proper tools, to remove the thin layer of wood that contains the accumulated color. One might do this for a gun which has been refinished, to complete the look--in keeping with Bill's advice.

To tell what a piece of wood will look like after a fresh finish, just wet it with your tongue. I'm not sure what you mean by uniform appearance...what most are trying to accomplish by applying a finish, in part, is to bring out the "character" of the wood, which is the variations of color that the grain of the wood presents.