During the manufacturing process, our soldering iron tips are tinned with 100% Sn solder to protect the iron plating from oxidizing. This process involves coating the the tip with the solder and heating the tips in a special oven to allow the solder to reflow evenly on the tip.
As part of our quality control process, random samples of tips are energized and manually re-tinned with the same 100% Sn solder.
Tips that were manually re-tinned as part of the sample inspection process appear to have a shiny appearance in the sealed package where other tips may appear to be less shiny or even a dull grey.
This appearance is normal and is a byproduct of the solder coating process in the oven. This byproduct does not have any direct or indirect affect on the performance and life of the soldering iron tip.
During the initial use of the soldering iron tip, the original solder on the tip is washed away as you tin your new tip with the solder alloy you are using for your soldering application at which time you will see that the end of the tip has a shiny appearance.