Check for duplicates against multiple criteria and then concatenate values

Hi there,

Hope this is in the right place - I've used this forum a lot to learn macro programming, but now I'm struggling with an element in a larger macro I'm writing.

For this section, I need to check for duplicates against multiple columns, and then, for duplicates, concatenate the values in one column into the cell of the row that is being kept. That might not make sense so here's an example:

Column A..........Column B..........Column C
Pen..................Blue..................Ballpoint
Pen..................Blue..................Fountain
Pen..................Red...................Ballpoint
Stapler.............Blue..................Desktop
Stapler.............Blue...................Heavy-Duty

I only want it to be considered a duplicate if both Columns A and B are the same, and then, if they are, I want to put the values in column C into one cell and then delete the duplicates - so my outcome should be:

Column A..........Column B..........Column C
Pen...................Blue.................Ballpoint, Fountain
Pen...................Red..................Ballpoint
Stapler..............Blue.................Desktop, Heavy Duty

I know how to check for duplicates against one column, but not multiple, and I'm also struggling with the syntax of how to concatenate the values, so basically I have nothing..

Could anyone give me some pointers?
Anything you can give me would be fantastic

Thanks,