I see alot of gun blue kits that suggest you can use it to "touch up" scratches. I've not had good success with it. Neither has the previous owner of a rifle I just bought. There are several tool marks on the rifle and I believe he used a cold blue kit to "touch up" those scratches. It covers the metal, but it doesn't look pretty. Do any of you have success with "touch up" blueing kits? Can you approach anywhere close to the original blueing or should I sand off the rifle and reblue the entire gun?