How to delete old backed up apps?

[MattBerry08]

I usually do the 3rd party backup including apps pretty frequently. Works like a charm. And I back up for other folks too - usually when doing OS updates. But I've noted that when reinstalling the new OS the list of "apps" to install (or available) continues to grow - now sometimes including multiple versions of the same app (if I've updated it). how do I clear this list without removing the prior backup files (or do I have to) -- I guess the better way to state it is, where does DM come up with this list of apps available - its obviously more than just from whatever .alx backup its pulling from.

Thanks all!