Yesterday, I was kind of moaning and groaning to myself that I couldn't remember how to fix backgrounds with mask layers in PS and my son heard me. He takes my computer from me and I'm thinking" What the...he doesn't know photoshop." and he finds a You Tube tutorial for me. So tonight, I wanted to use the history brush but didn't know how. I searched You Tube (after help in PS showed me NOTHING!) and there it was. It is so much easier for me to understand it that way than from reading books.
Here's a history brush one.