Just about every major city has at least one and usually several shops that specialize in radiator repair. They remove the "caps" or "tanks" of the radiators and run a rod through the small tubes. The process is called "rodding" the radiator. The parts are then dipped in a solvent and cleaned again. The radiator is then re-assembled and you are ready with a radiator that is like new. Some of the newer radiators, with the platic cans are not as suitable for this process. Also, the brass radiators can be soldered if there are leaks, making them somewhat more desirable. But then, some of the newer radiators seem to keep going for a long time, so it's all just a crap-shoot.