A Series Of SQL Queries:
DELETE content FROM content,metadata WHERE content.version=metadata.version and content.name=metadata.node and metadata_type='comment' and metadata_value='Some grammatical corrections' DELETE node FROM node,metadata WHERE node.version=metadata.version and node.name=metadata.node and metadata_type='comment' and metadata_value='Some grammatical corrections' DELETE metadata FROM metadata,metadata as metadata2 WHERE metadata.version=metadata2.version and metadata.node=metadata2.node and metadata2.metadata_type='comment' and metadata2.metadata_value='Some grammatical corrections'
This, for me, seems to have deleted the "Some grammatical corrections" spam I just got on the Open Guide to Boston. Someone more experienced with SQL taking a look at these would be much appreciated.
Of course, it's probably better to do this via $wiki->fetch_node, delete_node, etc. but I've never been one for doing things the right way -- I prefer the quick way.