In reply to Em66:
Just looked at my bottle of screen wash and it says 'if spilled on paintwork wash off immediately', so it's clearly not good for your cars paintwork.
If it were my rope and it had been soaking in screen wash for several weeks I'm afraid there's no way I'd use it for climbing again. I very much doubt any manufacturer would give you a different answer if you asked them for advice.
One to put down to experience, but on the bright side at least you get to go gear shopping
Mike