Here's from FAQ:
A certain amount of wear is normal for rods and we recommend conditioning your rod regularly. If you notice texture or color differences, you may need to condition your rod.
To condition a rod:
1) Clean it with soap and water thoroughly
2) Either place rod in oven at 250º F/ 120º C for 1 to 2 hours,
3) Or boil the dark grey portion of the rod in filtered or deionized water for 1 to 2 hours.
Conditioning the rod will re-hydrate the anodized layer, creating an even passive layer that yeast, hops, and their acids will have a hard time reacting with and therefore penetrating.
Sometimes very strong acids (star-san) and bases (oxygen cleansers) can remove the protective layer if they are exposed to the rod for an extended period of time. Therefore we recommend only using Iodine based sanitizers and soap and water to clean. If the rod is heavily soiled, half strength solutions of PBW (roughly 0.5oz/gallon) can be used for a period of 30 minutes at a time. Be sure to follow the PBW soak with soap and water to remove all alkaline solution.
If there is no grey layer left on your rod, discontinue use and email firstname.lastname@example.org.