I have an old homemade drum smoker that my neighbor built. It has not been used much (enough) and the grate is extremely rusted. Is the rust anything to worry about? Is there a reasonable way to clean it up? Should I replace it? I haven't done any measurements yet, but I think it is a 55 gallon drum that the grate needs to fit. Where can I find the material to make a new grate if necessary? Thanks!