Can sharpening a knife be done as a form of Ne'itzah for removing a Kelipah for Kashruth concerns?
Sharpening is the way mentioned in the mishnah in Avodah Zarah daf עה: 'ayin-heh, second side of the blatt. (=page 150) Look it up in TUR Yoreh De'ah 121 קכ"א
The end of the siman is dealing exactly with your question. The Beit Yoseph, who later wrote the Shulchan 'Aruch brings a lot of sources. Sharpening is also mentioned.
Please note that there used to be a major difference between small knives and big knives. Big knives were made from primitive steel (not stainless steel like today) and were always full of holes. The simplest way of cleaning a knife in those days, in the absence of soap, was to stick the knife in the ground where the earth was hard (usually a place where people walked) ten times (only three times according to a Yerushalmi.) This would wipe the knife but would not remove the food stuck inside the holes in the knife. In such a case the once-treif knife could only be used to cut COLD foods. Only heating the knife to a very high temperature could burn out food left inside the blade.