First of all, I have to say, radiator heat is wonderful. I love, love, love radiators. Heaven is leaving your bathrobe on the radiator when you go to bed and then putting it on in the morning. It has that just out of the drier feel. I'm leaving my gloves on the radiator near the door, so when I leave, the gloves are pre-warmed for my hands. Lastly, if I want to humidify the room I just have to put a wet towel or some sweaters that need to be dried on the radiator.
The problem was some rooms in the house were warm and toasty and other rooms were downright frigid. The radiator I looked at was cold to the touch. I guessed that the radiators had not been bled.
So I took my trusty radiator key, and bled the vent. What that does is release a lot of air. Rushing air, then followed by some friggin hot dirty water. The hot water is why you will need a cup to set under the vent, preferably one that won't transfer the heat to your hands. Try to bleed your radiators at least once a year.
If you have radiators in your apartment or home and one or more are nothing but cold metal bricks, you may want to try to bleed them. Please remember the scalding hot water that will come shooting out, if you happen to have the air vent open all the way. You can get radiator keys on Amazon or Ebay and possibly local hardware stores like ACE.