You don't have direct control over the status of the internal cache maintained by the Firebase SDKs. You can't delete or invalidate specific items.
The cache is completely managed by the SDK. The SDK determines when documents should be added or removed, based on whether or not they are in sync with the server.
You can use the SDK to delete a document, which will remove it from cached results. But that delete will eventually get synchronized with the server, and that's a permanent change.
If you have steps that show that the internal cache is somehow buggy or inconsistent with the contents of the server, then file a bug report with Firebase support that shows now to reproduce the issue.