I'm sorry you have to click on " Track Title" and then press control "A" and that will select all the tracks in your collection. Then press and hold control. Alt. Delete and it will clear everything from your collection.
How to delete Collection from Reckordbox DJ
Again ...lol I'm messing up here once you clicked on Track Title and press Control "A" then you have to Right click on the blue field and then you will be prompted to remove selected tracks from COLLECTION. I'm sorry while I'm not new to computers, I am new to Reckordbox and this is all a learning process to me. Repping That 610 DJ B.I.S.T. IS NOW DEFINITELY IN FULL EFFECT!!!!