Just a note - if the mod in question makes additional interactions available in the game, removing the mod while sims have those interactions queued will cause problems. Before removing such a mod do the following :
1)Load up the save
2)Pause the game
3)open the command console (Control-Shift-C) and do 'resetsim *', which will remove all actions from all sims
4)With the game still paused, save the game.
5)Exit the game.
It will then be safe to remove it.