Page 152 - Photoshop for Lightroom Users – Scott Kelby 2nd Edition

Step Four:
It’s likely there will be a few areas that have similar tones as the sky that will also have the sky showing through a bit, like the marble railing at the bottom
of the image, here (if you look on the right side of it, you can still see some of that sky showing through). To get rid of those areas with unwanted bleed-
through, click on the cloud layer in the Layers panel, get the History Brush tool (Y; I like to think of this as “undo on a brush”) from the Toolbar, then paint
over those areas and they return to their normal look, covering up the bleed (that’s what you see happening here, where I painted over the left side of the
railing). Paint over any areas where some of that sky is showing through—this should only take a few seconds and you’re done. Optional: If, after the
blending, you feel the sky looks too light in tone, go to the Camera Raw filter (under the Filter menu) and lower the Exposure a bit.