Best way to cut white products out of white backgrounds?



I'm doing some work for a bathroom retailer. They have cut-outs of their products against white backgrounds as well as some lifestyle shots. I need to start replacing the white background which means cutting out lots of white sink basins & white baths (as well as taps with reflective surfaces). What's the best way of doing this? I now magic eraser & background eraser don't work because they select parts of the products as well as the background. What's the best eraser settings?