I cleaned all my old bolts and had them plated locally about 15 years ago. I didn't know any better so I degreased them, glass beaded them and polished with a fine wire wheel. I remember staying up till 2AM to get them ready for the plater. I didn't know they may be able to strip them and then plate. That would have saved me hours of cleaning. I did yellow zinc, but silver was also available. This is what 15 year old plating on 50 year old bolts looks like. They do oxidize and get dull pretty quickly so probably best to store them in plastic bags. I suppose I could easily plate these again.