Operating system? FMP version? Clutter up exactly what list?
Exact information is helpful.
Filemaker Pro 10.0v3
The list is the list of recent files that appears in the box on the right when I open up the program.
Simply delete the file from your hard disk perhaps? If you really don't want the file anymore delete it and it will eventually not appear in "recent files". I can't understand why you would want to do this or why any of this matters, but perhaps I'm missing something.
In preferences in Filemaker, you can specify how many recently opened files are listed.
And in FileMaker 11, not 10, you can clear the recent items list. In 10, you'll just have to wait for it to drop off the list or, as David suggests, reduce the number of recent items that appear in it.
Have you found an answer in how to delete a database file completely? I would like to do the same. When I created a database, I made a mess of it and I would like to clear up the file listing and start all over again. Simply I want to make it look nice and not clutter up by useless database files.