Unable to delete Stale mongo data

Working with Data
1

I have a db with a collection of images with no references and the size has increased to about 160GB.
Now I am not able to delete any records as any operation times out. I have multiple instances of files, which can be queried. But the delete many and any other operation times out.

Pleas help

2

May be it is doing collscan
Are you using index on the fields from your query.Check explain plan

Check this link