are you talking about colour moire or luminance moire... different tactic for different problem...
for colour moire, very simple... create new layer, change layer blend to "color", use eye dropper (at 5 by 5 average) to select colour of the average moire area, and use a brush to paint over the affected area... alternatively, convert image to Lab colour, make a selection of affected area, and average the area in the a and b channels...
for luminance moire, more complicated... convert image to Lab colour, duplicate image, remove any signs of colour moire on the original image, now compare the duplicate image's a and b channel to see which resembles the luminance moire pattern, then while selecting "Lightness" layer in the original image, go to Image/Apply Image, "Source" select the duplicate image, select "invert" option, "Channel" select either a or b channel (using the one that resembles the luminance moire pattern) and then try to blend this into the original such that moire is reduced, usually with "multiply", "hard light" or "soft light" blending modes and adjusting opacity, then click ok...
hope this works for you
