Hundreds of voice clips in my timeline folder

There are not only timelines in my TIMELINES FOLDER.
There are hundreds of audio tracks. Every little voiceover test I did is there - even if I deleted the test right away after making it.
It's such a mess I can't find my timelines any more and must scroll endlessly.
Questions:
1. How can I prevent such audio files to be stored there?
2. 99% of those files I do not need - how can I clean this up without deleting audio tracks I actually use in projects/ timelines?
There are hundreds of audio tracks. Every little voiceover test I did is there - even if I deleted the test right away after making it.
It's such a mess I can't find my timelines any more and must scroll endlessly.
Questions:
1. How can I prevent such audio files to be stored there?
2. 99% of those files I do not need - how can I clean this up without deleting audio tracks I actually use in projects/ timelines?