Two issues spring to mind, many German daggers have crossgain which collectors like to see intact, and further polishing will usually remove it completely. The other issue is blade mottos and trademarks, polishing will usually effect the darkening within the motto and in worse cases will cause the sharp edges of the etching to round off. Also, many times its actaully the aging of the steel which creates greying or blemishes which acnnot be polished off anyway.
As you rightly say, they are quite different areas of collecting and preservation.
Red
