Lightroom, backup during import, then deleting original

[dbump]

When I import into Lightroom, I have the 'backup to separate location' option checked, and I point it to an external drive, so that I get images in two physical locations as soon as I import.
However, I've recently been taking a lot of experimental shots, many of which aren't turning out as intended, so I'm deleting them from disk as soon as I review them on the larger computer dispaly. Obviously, I still have a copy on my external disk. That's good and bad. If I mistakenly delete my primary copy, I can always pull a copy of the external disk. However, when I'm accurately deleting lots of bad images, I'm accumulating junk on my external disk.

I'm sure I'm not the only person doing this--anyone have a clever workflow for cleaning up your backup copy? I know I can just eat the cost of storage, but it's not just space, it's also managing content. The more stuff you have that you don't need, the more time you spend managing files, and the less time taking pictures, which is what I'd rather be doing.

[eddarr]

I do the backups later. My backup software runs about once a week and it includes more than just the pictures. This allows me time to delete the crap before it hits the backup drive.

[In2Photos]

I do the backups later. My backup software runs about once a week and it includes more than just the pictures. This allows me time to delete the crap before it hits the backup drive.
Yup.

The only reason I backup during import is to burn all originals to DVD. I do a separate backup for the actual files retained on my hard drive, as well as my LR catalog.

[dbump]

Likewise, I am doing a separate backup of pictures, catalog, .xmp, etc. on a weekly schedule, to a different rotation of external drives. But that alone leaves a long chunk of time that is unprotected against failure of my primary drive, which is why I use LR's backup during import feature. If (or should I say when) my drive fails I don't lose 1-6 days of originals.

I guess a certain percentage of junk data in my initial backup is a reasonable price to pay for the protection; I was just hoping someone had a simple technique for cleaning up said junk.