I
was doing some maintenance on one of the radiators today. It was only
heating up on one side and bleeding didn't fix it. So I suspected sludge
or spongy rust inside. A 2 l milk container fitted around the feed pipe
acted as a funnel and stopped water draining onto the floorboards. Had
to make an adapter for the garden hose from my ever-growing-larger
hoarded scrap collection and then gave the rad a flush. Seems to have
cleared the blockages.