Mass Contact Updates Training Webinar
Use DataMiner Platinum and the Excel Import tool to mass update information in the main contact tab.
Note: The training mentions that Excel Update can only be used to update Contact records, but the most recent version of Excel Update can now update all record types including donations. Just make sure to use the appropriate IPK field (e.g. DonationIPK, InteractionIPK, etc.) instead of the ContactIPK when updating a record.
For donations, watch the Mass Updating Donations Training Webinar.