Hi Raaghu,
Yes, indeed, after deletion with the Update activity, you will be able to retarget these people with previously mailboxes full.
The same idea for doing this, that I forgot to mention, is to update/modify the status to be "Valid" so they won't be excluded from further deliveries.
Then the nightly process manages them to cleanse.
But eventually, it comes to be the same as pure deletion, more or less.
But again, by retargetting these people with previous mailboxes full, most of them would have not purged their malboxes (if given up), so take care to your deliverability/reputation score with the ESP, monitor it closely, and smooth your delivery with small waves.
Regards
JS