It's quite easy. Basically i used magic wand with 45 tolerance to select the letters. Than go to select menu->modify->expand, and expand it by 2-3 pixels, according to the text size. After it go image->fill and set the Use method to content-aware, press OK and voilà, text disappers. After it use some spot healing brush, blur brush and clone stamp if needed to "fine tune" the result.