Is there an easy way to know who is spamming from my instance and contact other admins?

After the bot attacks I've cleaned up and implemented some additional measures thanks to some helpful users, but I'd also like to monitor the situation in case someone from my server decides to go on a spam rampage...

Is there a way to:

1. Easily get a list of comments from all my users locally and across the 'verse?
2. If I purge/ban these users, is there a protocol for letting other Lemmy admins know? I assume I have no power to delete things from their instances (just my copy of their instance?)