Thanks Aliya, for teaching me about FCP7 Render Manager. For many years I've been using Finder to remove old render files. As Nick says, it does the job. However it frequently does the job too well, so I discard render files that I need, and then must re-render.
With Render Manager, the current render files for each sequence within the currently open project are distinguished from the obsolete render files that appear in "Additional Render Files". When Render Manager says some render files are obsolete for Sequence X, it has checked that they are not needed for Sequence Y. Otherwise it gives the message:
Quote
Render Manager
Some selected files are used more than once and will not be deleted unless all their references are selected.
Then their only possible use is with an earlier state of the project, such as dug out of Autosave Vault. So they're pretty safe to discard.
Why isn't Render Manager working for Aliya? At first I ticked the head of the Remove column. No, you must tick the selected render file row in the Remove column. FCP7 Render Manager is based on old code, since it measures file sizes in the pre-Snow-Leopard way, but it works under OSX 10.6.8, 10.7.5, 10.8.5, and 10.9.5. I didn't check later OSXs.
Dennis Couzin
Berlin, Germany