When using Lightroom’s selective adjustment tools (such as the Adjustment Brush, Graduated Filter and Radial Filter), in order to reduce the effects of several sliders at once, click the disclosure triangle to the right of “Effect”. In the closed position (with the Effect adjustment sliders hidden), the Amount slider is revealed. Use the Amount slider to modify (increase or decrease) all of the Effect sliders at once.
Note: when using the Amount slider, all sliders are changed at once. This is very useful when a complex adjustment has been made using multiple effect sliders and you simply want to fine tune the intensity of the total effect and don’t want to have to manipulate each individual slider.
In addition, when using the Adjustment brush, positioning your cursor over the pin and click-dragging left/right (with the scrubby icon displayed) will decrease/increase the sliders without having to use the Amount slider.