Strength (1-100). The amount of influence on an image. As this parameter's value is increased, the degree of transparency left by the brush increases.
The Tolerance check-box lets you control the range of the colors to remove. By default the check-box is disabled, and the tool removes all colors.
When it's enabled, the tool samples the color in the center of the brush at the moment of the click.
Draw with this tool over the image, and the selected color will be erased.
The lower the value of the Tolerance parameter, the less colors are used. When the value of this parameter is increased, more colors are erased.