Remove orphan packages.

[Andrea Pretto <prettz_it@yahoo.it>]

Hi.

How can I remove from my system, a package1 that is  a dependency of
another package2 which have been removed ??

Example

Package A needs packages C, D and E.
Package B needs packages C, F and G.

Suppose I have just removed A, so D and E are useless.

Does exist such a way to print out, or remove these 'orphan' packages ??

Thanks in advance.