It is a letter opener with folding pen knife, Made by Imperial (USA)Looks like a letter opener?
I use Never Dull and then Flitz to clean and polish the knives after I do a cleanup/rust removal. I have a 1x30 belt sander, small jewelry bench grinder/polisher, but often I use different girt sanding paper and steel wool to remove surface rust by hand.What’s your cleaning process?