Hi @SeanMcC,
When you get to a certain scale of Subscribers, it’s surprising how many users have typos in their email addressees - this just happens especially when you have Single Opt-In forms.
The easiest way to do this in bulk that I have found, is to create a Segment of Profiles who have bounced emails more than X times - I use 3 or 4 bounced emails - but it varies on how frequently you email.
Then you can export that Segment as a CSV and then clean it up to be re-imported back into Klaviyo. Just note, this doesn’t “change” the bad emails, so you may want to Delete those profiles or suppress them. If there’s just a handful, you may want to consider merging the typo emails with the corrected ones.
Hope that helps!