You could accomplish the same results as the Photomerge Scene Cleaner by hand-editing areas between images, but it would take up more time. In the same spirit, the new Smart Brush tool offers a collection of common editing tasks that can be applied simply by painting areas of your photos.
For example, it’s often difficult when shooting to expose a photo so that the foreground is well lit without blowing out the sky; if you compensate to get the color of the sky, your foreground is often too dark. Using the Blue Skies component of the Smart Brush, you can select that blown-out sky and apply a blue gradient that restores the sky’s color. (You can also go crazy with colors; in Full Edit mode, the Smart Brush creates a layer mask filled with a gradient adjustment, so you can turn that blue sky into an orange sunset by editing the gradient.)
Other Smart Brush adjustments include a reverse black and white (keeping a foreground item in color while the background is black and white, for example), contrast changes, and Pearly Whites, which brightens teeth without all the trouble and expense of going to the dentist.
Blue Skies and Pearly Whites, along with Black and White–High Contrast are also available under the Touch Up category of the Quick Edit pane.