And it wouldn't be Nitty Gritty if I didn't bring back some...  moto gas caps.
 
This style being a Cam Lock (Bayonet style) Vented gas cap. The cap itself is chrome plated steel, and machined by a motorcycle parts distributor to ensure quality part. But the adornments upon it, are my silversmithing creation.
 
For this piece I have a made my classic sterling silver Venom pendant, a central diamond of Python shed, from my beloved Erzulie, rests under glass, a thick gauged rope wire edge around it, with high contrast patina to highlight it all. 
 
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Slight discoloration/firescale on the cap itself is natural, and unavoidable as it was heated to high temps to properly solder the sterling silver onto the stainless. It will look congruent to what you experience on parts of your bike that get heated up with active use. If you need a flawless chrome look, this might not be the cap for you. But if you like showing evidence of putting on those miles, it sure is.