The Magic Eraser tool erases (turns transparent) all surrounding pixels of similar color. In effect, this is like using the Magic wand to make a selection and then pressing Delete.
To use, click on the Magic Eraser tool and then click on an area of the image you want to erase.
For example, suppose you had a photo of a red car and you wanted to display some other image through the red paint. First, you put the other image behind the car (see Layers), then you would click on the red paint with the Magic Eraser for each panel of the car.
Increase the Threshold slider to increase the power of the pixel selection – 0 will cause only exact color matching and adjacent pixels to be erased. 100 erases the entire image.
See also: