To start, ensure the radiator is switched off so there are no safety concerns.
You should fashion a cleaning device consisting of a thin stick or wooden plank, also featuring a towel or cloth attached at one end.
This item will allow for you to reach the narrow gaps in between radiator fins on a convector radiator for instance, tackling any dirt or dust that may potentially build up and cause blockages, or prevent the radiator from delivering its optimal heat output.
To find out more, take a look at our blog, How To Clean A Radiator.