Nah,
theres a thing to clear it but on FF1.5 there was an option for all downloads to clear as soon as they finished. It's nothing major.
( Shuya Nanahara Sayonara, Tue 5 Dec 2006, 9:48, archived)

the "Remember what I've downloaded" checkbox
in FF2 has the same effect
( pzyko is a whaler on the moon and carries a harpoon, Tue 5 Dec 2006, 9:55, archived)