The best and also the, by far, safest methods of removing gold plating are filing, grinding, sanding or polishing the object in question. There are not any known chemical methods that are non-toxic and truly safe to use. Also, in most cases, the amount of gold used in plating is not worth trying to reclaim for scrap value.
Use hot water to soak the object for 10-15 minutes. Rub off plating with a hard white eraser. Gently use a flat razor blade to remove what the eraser left behind. A Dremel may be used to remove the plating and polish the surface to prevent further damage.
The process of creating "gold" legs is accomplished through the process of anodizing. Over time, the anodic coating can get beat up, trashed out and look bad. To make a pin look new again, people usually replace the ratty looking gold legs with new ones.