Cleaning old transparencies?

[aprisa]

Stupid question maybe but...

What should I use to clean up old slides before scan them to remove the finger marks of 40 yrs?

Cheers
Nick

That's assuming my new scanner arrives today :)

[scalper]

You could try Pec12 (it gets rid of anything except water marks) but I'm afraid that a fingerprint which has been on a slide for such a long time could have caused permanent damage to the emulsion.