dont get that with my heated windscreen ;)
if you're getting it alot though buy a bag of desiccant like this but not nececarily this you can reuse them by popping them in the oven for a bit too. i used to get this issue ALL the bastard time with my old gti golf, gti swift, mk2 excort and for granada... do this and problem solves ds mate.
working in engineering i just used the silica bags we get in the crates with the castings :)