How do you patina? Is there a 'frugal' way to make a surface look like it has been oxidized (out in the elements for several years) 'without' purchasing a product from a store?
It depends what type of surface you're talking about. I remember reading somewhere that to make new gold knobs or hooks look old, you'd soak them in a container of ammonia. The ammonia eats through the clear sealing and will tarnish the object. I've also seen fake "patina" done with paints.