When we buy a new vessel, there will be stickers of the specific brand or the bill .When we use the vessel as such / try to wash them, it may mix with the food while heating the vessel or will not go completely from vessel.
Before starting to use the vessel, show the reversed part of the vessel where the sticker is fixed ,into flame directly for some 3 minutes and use some knife or spoon end to remove it.It will be removed very easily without leaving any marks.Its my own experience.