Best cleaning method for old lock .

[TTinCa]

Found this at low tide in brackish water near San Francisco Bay . It has a thick encrustation on it . Does the green color signify anything ?
How would you guys go about cleaning this ?
Thanks TT

 

Amazon Forum Fav 👍

A History of Mining on the Kenai Peninsula, Alaska - Grab it through Amazon!

[lastleg]

The green stuff is verdigris and means the metal has copper content. You can remove it with a dremel
tool with a brush attachment but it looks good as it is. Not valuable in either condition.