I don't know if you can remove individual entries but you can change the number of documents listed by going to Edit, Preferences, General, and change the entry for 'Maximum documents in most-recently used list'. The minimum seems to be 1.
Fujitsu Lifebook P727 laptop review
Best of the Grad Shows 2017: University of the West of England (UWE)
Best value Mac: Which is the best £1249 Mac to buy
Les meilleures GoPro 2017