Hmm, never had to resort to anything else. The wink usually works. 
Fine…I can SEE how one might think you’ve got something in your eyes. That’s when you go for something that’s more…erm…foolproof and obvious. Something that can’t be doubted…like…this:
Can’t get any more obvious than the repeatedly uppy-downy moving eyebrows. If she smiles and looks down…and starts sharmaying. It’s a good sign. If she eyebrows you back…even better. If she freaks out or give you a dirty look…it’s a no-go. That’s why they say actions speak louder than words, 