Long story short, a client had 300,000+ entries come in through a form, which caused the database size to swell, exceeding the storage capacity of the VPS and causing the site to crash. 

I was able to manually delete all the entries from that channel from the craft_entries table, which got them back within storage limits and go the site back online. Rebuilding the search index got that table back down to a normal size. However, both the craft_content and craft_entryversions tables are still measured in GB.

I don't know much about the database architecture in Craft, and raw MySQL is not my strong suit. Is there anyway to cleanup those tables based on a channel? As in, I need to remove any stored content that's related to a specific channel and leave the rest of it in tact.

Any help would be greatly appreciated. Thanks.