Thanks touch typist.  

Well, that shows how an amateur can cock things up.  I thought the optic sensors looked like glass, hence I thought alcohol (Meths) would be ok, I am assuming they are some kind of clear plastic then? doesn't appear to have done it any harm, i.e no hazing.  

I don't have any contact cleaner and don't want to spend any money on the thing since it was free and I have no money

I've put the daisy wheel on eBay and the ribbon and correction cartridge.  

I sold a daisy wheel the other day for 7.99 for a machine that cos me 1 pound to buy but I could never get working because the plastic gear which powers the platen was broken.  Maybe someone will want a 1988 Olivetti daisy wheel and ribbon.  The thing is ridiculously huge, its about 4 inches either side bigger than a conventional pc keyboard. When you pick one corner up, the other corner stays on the surface like a cheap sofa! the thing has no screws its all squeezed plastic clips so I'm not that bothered about it. I spent an hour or so trying everything to get it working, its ugly, plastic and fifty and takes up the width of a cooker.

Really appreciate all the help though.