How to remove unused columns and eliminate warnings

I have hundreds of these I think mainly due to the way the union all task works. Any ideas on ways to eliminate these?Select the connections in the editor and hit the delete button.
K|||

I guess I wasn't clear. Those columns are used earlier on in the data flow so I can't delete them from the connection. However I get incessant warnings about them hanging around later in the data flow.

|||Chris,

could you give us more details? How did those columns get generated?

That might give us a better idea if you can get rid of them.

Thanks,|||Just an idea... As far as I understand SSIS columns are "recreated" behind an asynchronous transform...

I.e. when you have a source with 2 fields (A and B), a derieved column task which calulates C by A+B, a sort by C passing A and B through it and a destination where you write A and C in a file you should get a warning that B is not used and can be removed... That's because B is passed through an asynchronous transform so it's a new column. And in fact, it's not used behind the sort...

At least that's how I understand SSIS...sql