How to use the Unused Column?

Hi,

One of our developer has asked this question.

"In our project we plan to drop some columns as we anticipate not to use these columns. We do not want to drop the columns completely out of the database and completely lose them, instead we would like to use the unused columns feature in Oracle 10g. From the documentation I have read so far, I could not find anything that says we can retrieve an unused column and remove the unused mark against the column making it available for use"

The development team would like to re-use the column if needed in the future. Is there a way to do it or Once you set it unused you can't get the column and data back?

We are at 10.2.0.2 on HP-UX 11.11.

Thanks
Raja.

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