I'm sorry to hear about your bulk deletion issues with RSS feed content. For Jive Cloud, you may be able to use Bulk Content Management as mentioned here:
And covered in the Jive Cloud documentation here:
If you're on a different version of Jive, you'll want to consider using the Curate Tool, which is available through Jive Professional Services (PS), or you may develop other options through Jive v3 REST API. For the latter option, this falls under development and will be outside the scope of Jive Customer Support, so any questions should be posted to the Developer space for insight from the greater development community.
I hope this helps. Let me know if you had any other questions or if you'd like to be put in touch with our PS team.