Clean up color artifacts in LAB color mode

I get a lot of crusty photos from clients. Here's a tip on how to get
rid of a lot of the color noise in JPEG compressed images.

1. Open the bugger in Photoshop
2. Change the color mode to LAB (IMAGE>MODE>LAB)
3. Open the channels pallet, you'll see three channels LIGHTNESS, A
and B the A and B channels are the color channels
4. Select channel A and apply the Median filter (FILTER>NOISE>MEDIAN)
5. In the Median filter dialog box choose a setting that gets rid of
the blocky artifacts
6. Do the same for the B color channel
7. Viola! no more color noise you can then convert the image to RGB
or CMYK