To begin with, you need to make sure your radiator is turned off as a safety precaution before cleaning it.
Be careful to eradicate dust from between any radiator panels, so the component can perform to its full capacity without the distribution of heat being blocked at all.
You can do so by creating a cleaning device from a thin stick or wooden plank, and attaching a cloth or towel at the end. Such an item will enable you to reach awkward, narrow crevasses and get rid of dust and dirt that might cause blockages.
As it pertains to the radiator surface itself, you can use a soapy water-laden sponge to combat markings or stains.
For a more detailed insight, take a look at our dedicated blog, How To Clean A Radiator.