I have found that OLD formula of Hoppe's #9 on a rag gets the number off very easily and leaves a smell that is normal around guns. After lightly rubbing the number off, I lightly wipe the rest of the box to make everything even. After the "wet" wipe, I go over it all again with a dry rag. What you are getting off was applied with a "grease pencil" or sometimes called a "china marker". The NEW formula of #9 does not seem to work as well. Have tried Goo Gone and find #9 a bit better. Hope this helps.