You'd need to thoroughly clean up and re-seat an egr valve, all the used ones I've seen have been covered in burnt black yuccy stuff, you also might need a rust preventative in the water to stop the valve rusting, they are usually cast iron.
Beware american made fords use NPT threads, uk made BSP, if you care they dont fit, if your ham fisted they do.
Boilers tend to have copper and cast in them, both valuable as scrap, leave one by the road and I bet it'd be gone before morning.