Or the marks could be left, after washing, by a rusty iron.

There are even real bits of this corkscrew escalator-ramp thingy - timber and rusty iron chains - on display.

It was the time of year when wayside plants are drying up - docks the colour of rusty iron; mallows hanging limp.

Its rusty iron surfaces, meanwhile, seem to expand the artistic conversation quickly to issues of ecology and the despoliation of the natural world.

They were rusty iron bedsteads with two-inch horsehair mattresses.