Darrin, oil may be aright for lubrication or for combating rust issues on steel but I am afraid it's not of much use in retaining a luster on metal surfaces. Oil and waxes have a penchant for attracting and retaining dirt. Some will suggest the use of clear coat lacquers as there are decent products available on the market for doing so. The downside of these products is 'if', any of the surfaces treated with these coatings get compromised, due to either poor application or from getting scratched, the substrate metal is exposed to the air with the result being a tarnished appearance. The only way to resolve this condition is to strip the entire piece and re-apply the coating as no amount of area prep will result in a decent finish. A good metal polish, some clean, dry terrycloth or gauze pads coupled with a bit of quality downtime with the metal pieces will yield a shine that will endure quite a long time if the pieces are not handled. Again the oils on ones skin attract dirt and are transfered to the metal along with, in some instances, ones sweat is slightly acidic which also does not bode well for a good shine. It has been my experience that a quality shine begins with the surface preparation. The more machining and tool marks one can remove from the surface the better. Going over surfaces with progressively finer and finer grits of abrasive paper followed up with a session of polish will put a smile on your face, one that you will be able to see in the finish. An occasional follow up with the polish and clean cloth every couple of months is all that is required to keep things nice and bright.
BC1
Jim