Macro To Detect Cell Colors

We have a workbook with over 20 worksheets, each sheet with one or more tables in it. Several people use the workbook and we have decided that when someone changes a cell, they should mark the changed cell by filling it with blue using Format Cell. We have then nominated one person at end of each week who will check all the changes made during the week and either approve or reject them. So her task is to find all the blue cells, check them and then take the shading off.

What I would like to do is to create a macro to help her. I would like the macro to automatically identify all the blue cells in the workbook and give her a list of these cells. I wonder if someone could give me direction on a couple of things:

1) The command in the macro that would return whether a cell is shaded blue

2) The way in which I could cycle through all the content of each worksheet. I'm thinking worse case I would have to write instructions to go to each sheet, and then do an outer loop to go through each row, and an inner loop for each column (and the number of active cells varies by worksheet) -