Plinth Country have posted a tutorial, on their blog, showing a technique to paint and weather a sci-fi display bases.
From their announcement:
I’d like to announce last night new text has been added to Plinth Country articles section. This time it’s about rusty way of painting the display base about which you could read in the previous article. It’s actually the easiest and most effective way of painting rust I could find during years spent in the hobby.
I hope you like it and find the stuff useful. If so I have good news – yet another text is being prepared now and it will be posted as soon I I get house renovation finished