The easiest option might be to add a blanket expiry, to the relay settings. (1-2 weeks). To standardize this for nostr, we could add NIP11 display for DM expiry info. There were other options like allowing deletes of anything that you are p-tagged in, or by kind (1059 in this case).
@Vitor Pamplona mentioned it would be cool. It could be useful but seems hacky and requires a lot more custom events be sent.
The other thing to pay attention to is, we can only control the fine grain aspects of this when looking at WHO we are DMing, and if their settings use less-private or relays without this feature, you can't have your expiry. So clients need to be up front about what giftwraps are going where BEFORE sending.
If we do all these things, the NIP17 will flow. :)
