Mk3 Fiesta Starting Problems

I have a mk3 1989 G Reg Ford Fiesta, and at the moment I am having problems with getting the thing started. Sometimes it will start fine but sometimes it just will not start, I turn the ignition and absolutley nothing happens, its not even trying to start. I have been told that it is probably the starter motor from a friend and from reading another post on this forum. Im wondering whether I actually need a new starter or whether removing it and cleaning it up will do the trick? Any advice would be much appreciated.
Cheers