How do I clear Active Directory attributes using either LDIFDE or another script?

I am trying to clear the values set in Active Directory for the following attributes: mDBStorageQuota, DBOverQuotaLimit and mDBOverHardQuotaLimit.
Ideally I would have a list of DN's of user accounts with these values set and then run the script against these DN's to clear one or all of the three attributes mentioned above. In the Exchange 5.5 days these attributes could be cleared by importing "~DEL", which would remove whatever value was set. Is there something similar for AD?

Any help with this would really be appreciated.

Thanks,
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