It depends what you mean by ‘average’ condition. If it’s just a bit dirty with light surface scratches and swirls it can probably be polished by hand with a good polishing cream like Autosol. If things are a bit worse than that you’ll only get it shiny again with a machine polish. That involves removing all the panels obviously. The other option is to go for a brushed finish which will hide more imperfections. Not sure that would look all that good on an all stainless machine though.