Is there an eco-friendly option for metal spray painting, powder coating, sticker printing and adhesives?
Most likely, what you are getting is the greenest option. Most likely your customers are more worried about rust and other bad things happening to the metal than they are about the green option. You may find some non-toxic adhesives that work as well as the toxic adhesives such as some rubber glues. Powder coating I have always lead to believe was more environmentally helpful than past ways of doing things.