New here and curious of quality knife I have. It is a Spyderco, engraved MILITARY, CPM440V, (4" blade,)Colorado, USA. Has pocket clip on one scale, three screws hold it on and they came loose and lost one, but retained clip and two other screws. Probably some 10 years old or close to it and good shape, but dull and I can not sharpen the thing. Is it any good and any suggestions on sharpening blade?? Any and all help appreciated.