Column duplicates - how to clear cell entries three columns to the right

I have a spreadsheet which is being exported erroneuosly from a database, I have no access to the database so I now need to work with the spreadsheet it output to trap duplicates then clear some cells a few columns away.

the duplicates in a column are very easy to trap, I used conditional formating then a formula like this ....

=COUNTIF($A$2:$A2, A2)>1

this highlights all duplicates in Column A (not the original copy, just the duplicate) , but the thing is I don't want to delete the duplicates appearing in column A, but rather for every duplicate clear the contents of a cell on the same row, but three columns to the right.

Any ideas how I could approach this (ideally I'd like a macro, but I'll try anything for now!)

This might help (I want to clear the cells highlighted in red in column D (headed 'Postage cost')....

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Once you've highlighted the duplicate cells with a color (say yellow), then you could filter all the columns by the first column's color (filter by color). Then select the cells that are three columns to the right that you want to delete and delete them. Does that work for you?

Yes that idea works but are you saying this task can be done automatically or manually?

I have the duplicates in the first column (column A) highlighted in red already...I therefore need to automatically find all red entries in column A, then once a cell with red in it is found clear a cell on the same row but three columns to the right.

So it's this last bit that I don't know how to approach - any top tips?!

This task is done manually. Let's say that the three columns you are working with are titled with the top cell of each column being Alpha, Bravo and Charlie (respectively from left to right). Select those three top cells (Alpha, Bravo and Charlie). Then, go to Data-->Filter. Once you choose filter (sometimes it is called Filter and Sort) this should bring up buttons on each cell (Alpha, Bravo and Charlie). Click on the Alpha button and there should be some options to filter by different criteria. Filter by color and you should get all of those red cells to come to the top with the corresponding content in columns Bravo and Charlie staying in line with where the Alpha content moved.

Let me know if that works for you, otherwise I can try explaining it again or putting a sample spreadsheet up as an example.

Many thanks...that manual method works - it's a shame it can't be done with a macro, but for now I'll use the manual method :-)