Take a look around your house. Are there any radiators that double as shelves and are collecting books? Or piled high with toys? Maybe there’s one hiding behind the sofa… Let’s straighten things out once and for all; anything obstructing the radiator restricts the air coming out and increases consumption.
Putting your underwear on them to dry isn’t a good idea either. Unless it’s pouring with rain and you’ve run out of clean socks, try not to do it. The radiator isn’t a clothes horse. The flow of warm air is obstructed, the house won’t warm up so quickly and the boiler will have to work harder, driving up the power consumption.