Is It better to remove the tiny spot or not

From my last entry of my journal I mentioned a coin a 1925 1 krona that was in beautiful unc condition. what i failed to say is that this coin even though it has a wonderful chartwheel, but seems a little dull to me and i think that maybe a little conservation may help it along to a possible MS-66 and or better. And having a brass coin from Iceland that I sent to NGC last summer for grading that came back a MS-62 with note attached to it saying that this coin is a good candidate for conservation and knowing that the coin is much much better then a MS-62 maybe a 65 or better . now mind that this coin is a commemorative and never was placed in circulation, they are very tough on grading of Icelandic coins and medals. I also found another coin at the New york show this pasted weekend it nearly knocked me over when I took It out of its white 2x2 envelope It was a 1937 25 Aurar It was like a sparkling diamond, never seen such a bright 25 Aurar in my life. Buttttt, It has a very very tiny spot on the edge of the rim. Under a 17x glass it seem like tiny spot of gunk. And I also found a proof Icelandic 2 Kronur From 1962 that I was told from another dealer at the show that I know that, this coin has a film on It. So back to the start of this entry do I conserve all these coins or not , were does it end. I'm not made out of money. Even though my 12 year old daughter thinks so.