Remove key based on value in Hashtable

From: bunallo (nmnm_at_alala.com)
Date: 02/26/05 

Date: Sat, 26 Feb 2005 02:12:57 +0100

I have a Hashtable that never contains duplicate values. The problem is that
I in a class only have access to the values of a Hashtable an not the keys.
I would like to be able to removed keys in this Hashtable based on values
and not keys is that possible??